I'm surprised you blame yourself for being angry and frustrated at your friend's lies, saying that you "drove her away" when it was she who found the friendship a burden in the first place?

If someone decides they don't want to be with another, there's not a whole lot the other can do about that. Moving away from the person who doesn't want to be with you is usually the best choice. But your friend should not have lied to you, ever. She should have said, "I don't want to maintain this friendship anymore" and made it clear to you she did not wish to see or talk to you again in the same close way she had before. Your anger and frustration at her lies was a good instinct on your part but I would not have followed it up by continuing to deal with her.

You cannot make this person be a friend to you like she was in the past. The past is totally gone. Your friend has moved on from the friendship; that is clear in her not contacting you in any way, not responding to your card, etc. She does not want to be friends with you! This does not say anything about you as a friend, just that she, personally, does not wish to have you as a friend. You have your time and very life to lose by persuing this person. You should be looking for other friends who are "friendly" :-) to you. You are too obsessed with this person, find other people who can respond and give you love and comfort.