Advice needed about friendship

OK so this might be a bit of a novel so I apologise. I think I have the comment function fixed on my blog so I would really appreciate some advice - I am a bit torn on what to do here.

Before working at my current job I worked at a jewellery store with a gorgeous bunch of girls. While I haven't kept in touch with absolutely everyone I worked with there, the time I spent working there was great, and there are a select few girls whom I definitely have kept in touch with and whom I consider to be true friends. My "best" friend there was "L". She and I spent so much time together, went out together a lot, had dinners at each others houses. She was my bridesmaid at my wedding and in all honesty was a tower of strength for me during the wedding planning, as I was dealing with problems with my sister at the time and was under a lot of stress. She organised my hens night, my bridal shower, went shopping with me, all that bridesmaid stuff. She even babysat our cat while we went on honeymoon! I took her out for dinner and to a concert to thank her for all she did for me.

After I left the jewellers and started my current job, we were still just as close. She and her partner moved house and she called me and invited me to a housewarming party they were having. I told her that it was the same day as my dad's birthday and so I would come to her party later in the night once I had had dinner with dad. The day before the party my dad was admitted to hospital with pneumonia. We were all quite worried and I wasn't in the mood for going to "L"'s housewarming as I wanted to focus on being with my dad. I tried calling her mobile (cell phone) but I got a message saying the phone had no signal and I would have to try again later. I tried many times over a 24 hr period and kept getting the same message. It was not uncommon for L and her partner to go on short holidays. I wondered if maybe they were away and therefore were somewhere that her phone wasn't getting reception. Maybe they would be returning for their party that night. I wasn't sure. So in the end, even though I hate cancelling on people through text message, I sent a message explaining about my dad and saying I wouldn't make it to her party. Because she had just moved house I did not have a correct home phone number. I also want to say that I rang the jewellers where she still worked. None of the girls there were going to the party but I left a message at the store anyway.

Weeks went by and I heard nothing from L. I tried calling a few more times over the next two weeks. Sometimes I would get the funny message on her mobile, and sometimes it would ring with no answer. I thought nothing of it, and assumed she would get back to me at some stage. This co incided with my egg retrieval surgery for our first IVF cycle. Then a few days after the surgery I was admitted to hospital with ovarian hyperstimulation syndrome and stayed there for over a week. Our embryo transfer had to be cancelled and our 9 embryos had to be frozen. It turned out only 2 were suitable for freezing so we lost 7. I blamed myself because I had gotten sick and when I returned back home, still not feeling the best physically, I was also really broken emotionally. On that first day home I laid in my bed all day and cried and felt so low. Then my phone beeped and it was L. She had sent me a text message abusing me for failing to show at her party which by this time was over a month ago. She called me some horrible things and said that I had become obsessed with trying to get pregnant and that obviously all I worried about was babies and myself these days. She obviously had not got any of my messages and so as far as she was concerned I had not showed up and hadn't even called. She had no idea of what was happening in my life at that time, and her text just happened to come on the worst day but I found it so petty when I had just been so sick and lost all but 2 of our embryos. My feelings were hurt too because anyone who knows me would know I would never not show up to somewhere I was expected without notifying someone. I would expect a close friend to know this and to give me the benefit of the doubt and at least call me to get an explanation before getting mad at me. Also in her rant she said something like "and if you are wondering why I am bringing this up now its because my phone has been broken and I have only just got a new one". I thought well if you know your phone hasn't been working why do you automatically assume I haven't called you? For all you know I have called many times (which I did) and have not been able to get in touch. Why then would you choose to abuse me without checking the facts first?
In my anger and upset I sent back a short message saying I didn't want to be friends anymore and for her to not contact me again. That was it. No explanation, no abuse back.

Several years have gone by since then and we have not been in contact. A few times she has tried to get back in touch with me but it has been done in a way that I have not appreciated. What I mean by that is that obviously I am not perfect and no one is, so obviously from time to time we say the wrong thing, lose our temper etc. I am a believer in forgiving things like that within reason as long as I get an apology. If I did the wrong thing I would give someone a call or go over to their house and talk with them face to face. I would say "Hey, I am so sorry. I did the wrong thing. I said an awful thing to you. What can I do to help you forgive me because I feel terrible I have upset you? etc". Despite my phone numbers or address not changing since she was in contact with me, L has never tried to call or come over. Once she sent a Christmas card but all she wrote was "Dear Jo and family" and "Love from L" with the printed greeting in the middle that is put in the card at the factory when it's made. She didn't write anything extra. A couple times she has bumped into friends of mine and asked them do they still keep in touch with me. When they have said yes, she has asked them to say hi for her. I know some people would see this as putting in an effort but I feel the effort is minimal and in a way it kind of makes my feelings even more hurt that she hasn't done more. I also know that once when she bumped into a friend of mine, my friend told L all about the fact that I had tried to get in touch with her to say I wasn't coming to her party, that my dad was sick etc and also told her that her nasty text had come on a day when I had just come out of hospital. Even after knowing all of that, that is the best she has done to try to be friends again. Others will say that I should be the bigger person and extend my hand in friendship to open the door again, but I just don't believe it should be put on me when I feel like I did nothing wrong. I know that is stubborn but that is how I feel.

Anyway today she has sent me a friend request on facebook. She hasn't written anything on the message, just sent the request. I have no idea if I should accept it or not. Any thoughts??? :)