Conflicted

So, about a year and a few months ago me and my ex broke up. Recently my ex’s mom has tried harder to get into contact with my mom they were pretty good friends during the relationship. She added her, started to txt her, commenting etc. Well today I found out from my mom that my ex has been trying to contact me via number which is my old number. His mom had told my mom he tried to call me but it kept going to voice mail and she told him to stop because I have a boyfriend so he fought with her because he told her it was all her fault we aren’t together anymore. That it was too late. She keeps contacting my mom about stuff she has been for a while. I am so angry and confused because he treated me so poorly and now they’re starting to do that to me. I asked my mom to stop telling me things about them because I no longer care but it is so upsetting.