Over a year after I've no longer been using suppli...

Over a year after I've no longer been using supplies from them and I am STILL getting bills from them! I have called and paid everything up and then a few months later they send me more bills!! When using the service, I would have to call every month just to receive the supplies that I needed!
I am so thankful I don't need supplies from them anymore but I'm so fed up that I am still spending hours on the phone trying to figure out where they are coming up with more bills that didn't even exist last time I called them!!