Driving me insane

I opened an account with homechoice/fonechoice a couple of years ago. The accounts have been fully settled. However, I receive marketing phonecalls from them on almost a daily basis. Sometimes I have received upto 5 phonecalls in one day. Now I have caller identity and have blocked most of their numbers. And on NUMEROUS occasions, I asked them to remove me from their database but the pestering continues, even after hours and weekends. I have had enough. What must I do to just get them to STOP?