Trezure2, what if you made a list of three or four reasons not to call your mother? And every time you feel like calling, make yourself look at that list again and maybe add another reason.

It may also help to post on here when you feel like calling but don't really want to - I had a friend going through a similar situation so we would contact each other when we wanted to call our toxic person and then remind each other why that was a bad idea.