Random FaceTime calls

So for the past 3 days, a group of immature kids have been Group FaceTiming my phone and it’s to the point where they would call every 2 minutes non stop. I asked for them to leave me alone, delete my number, stop calling and they would not. Everyday it seem like they kept adding my number to another group. So I decided to blocked all the numbers in the group and for a couple hours it stopped and I thought it was over but now I just keep getting the Notifications at the top over and over and when I clicked on the FaceTime app, I can’t delete the group or nothing it only keep saying to join and the icon next to it is green. P.s it says blocked cus I thought maybe by blocking the first number it would stop but it didn’t.