I'm so sorry to hear this, Nate.

You're incredibly strong. It kills me that you had to go through all of that. You're amazing.
But luckily, youv'e done well for yourself and hopefully you've lived your life happily as an out man.
Now that you've got your bearings straight and you don't depend on anyone anymore, I think you really have the upperhand as for what to do with this phonecall.
I think a part of you will want closure, which is why I think it's worth calling them back. You can look at it this way:
You've proven that you will never have to answer to them ever again and that you don't even need them. So your mother may want to talk to you about two things (the points of interest, anyway):
1) She's come to her senses and she's sorry and weeps bitter tears of remorse along with everyone else in yoru family who threw you away like the good Christians they aren't.
2) She wants to know if you ever worked out your problem and if you have, is willing to let you come back for some reason or another.
If it's 1, then you get a chance to forgive them (if you want to) and build a new relationship with them, which is only, again if you even feel like you want to.
If it's 2, you get to tell her off and rub it in her face that she abandoned you and tell her what terrible people and Christians she and your family (and your 'friends') are. Tell her that's she's a selfish, wicked, woman (you being gay ruined
her life?) Then you get to add that if this is how she is, she doesn't have to bother trying to contact you again, because frankly, you won't bother picking up because she has nothing you could ever need and (this is my personal opinion) she's hardly worhty of being called a mother anyway.
So call her back. Treat her like a strangershe deserves to be treated like and find out what you need to find out for closure, and then get the apology you deserve or the last laugh that you deserve. Both of which are completely your right.
Sorry, your story got me really steamed. People who do this to their kids don't deserve to live. I'm merciless in this respect.
Welcome to the board. You're an inspiration.
I also agree with Chris3800. Let her wait...make her wait a week or so. Call her when you're bored or something, between actual important things in your life. In every aspect, you have the upper hand here. Now make them sweat. Crush them.