How to get rid of toxic friend?

I have a childhood friend who I can't get rid of. She is very toxic, basically a frienemie. Her and her family are very obese, she used to get tormented as a child so overcompensates by acting like she is better then you, gossiping non stop, I mean to the point that her and her mother sit at the kitchen table talking about people. Though I've known this girl for so long she knows nothing personal about me. Every time we talk it's about her giving me more gossip on people I have not seen or spoken to in about 10 years who I don't care about. I don't share details about family matters, my relationships with guys, work matters, nothing with her. As we got older I realized we had 0 in common anymore and I would stop retuning calls, we pretty much never hung out as I knew that she was only interested in more gossip bc the girl has always been so miserable with her life. I also stopped being friends with my old circle as I wasn't into the party scene anymore and have different priorities now. I have tried for the past YEAR to get her to stop calling. I don't return calls, haven't in about 5 months every call unanswered, don't answer any ims or texts though I said thank you when she texted me happy thanksgiving yet she continues to call. I would rather have no friends, though I have a loving boyfriend who is my best friend and wait to meet true friends. Should I just change my phone number though I would rather not bc I feel like I have a stalker on my hands?