What should I do?? :(

Almost a year ago I stopped being friends with my bestfriend who was really my only friend. I put an end to our friendship because she was accusing my boyfriend and telling everyone that he was a fellon with three fellons and that he had hit a girl before. None of which is true. For the past year, a mutaul friend and the girl herself have been trying to get me to talk to my old friend again. I was always refusing and ignoring them when it came to that subject. But now for about a month I keep thinking about how much I must have hurt her and want to send her a message but Im no sure if I should be doing that. Its been about 4 months since she has tried to get ahold of me so I dont know if it will do any good. What should I do???