Well all I can say is - if it's bothering you a lot, then tell her you don't want to hear it. If she starts, hang up or leave - eventually she'll figure it out and stop, and if not - cut her off.
Either way, YOU determine how people treat you - once you decide you won't be treated that way - stick up for yourself and be firm - only allow her to treat you the way YOU want to be treated - and if she doesn't change then you are going to have to make the change. I had to do this for my own sanity - but, it took a long time before I finally stood up for myself and put my foot down - she didn't change though, and my only recourse was to completely end the relationship.
Hopefully for you, it won't get to that point.
EDIT -- I also wanted to add that I have a lot of support - EVERYONE in my family knows how she is and none of them get along with her either. Her sisters are "cordial" at family functions - but none of them have anything to do with her. I will say hello to her at a fam. gathering, but that is it, we don't have anything to do with each other - in fact, we NEVER speak otherwise - even at fam. gatherings she won't even acknowledge her grandkids or speak to them or hug them..... she is a cold cold cold nasty person - my youngest for a long time (and he's only 10) thought my aunt was his grandma!!!! My older boys NEVER speak to her - but, then again, she's never wanted anything to do with them. She ONLY ever wanted to be involved with my sisters DD who is now 16 - NO, they don't speak anymore either, she constantly put my sister down and ran her mouth about her to my sisters DD when she was with her, and that is when she was little - she is truely a brutal wicked evil person. ( She actually had all the grandkids at her house one day in the summer many many years ago -she was "babysitting" my sisters girls, so she wanted the boys to come over too........ - anyway, one of my sisters girls went inside and got an apple off the counter - she came back outside with it and her other sister saw her, so she went inside to get one, well, when my mom saw her with it........... NO LIE, she called the police to come get her for stealing!!!!!!!!!!!!!!! ) This is a TRUE story - my sister called my hysterically - it was a huge blow up - I thought my sister was going to kill her - but this is one of the TAMER - MILDER things she has done)!!!!!