Wealth Destructor, which is more important to you, money in the bank or not having to answer the cell phone all the time?
Next time they call, I'd answer the phone and ask them for their company name and address, then tell them that they no do not have your permission to call YOUR cell phone.
The next time they call, I'd answer and say to them that I was recording the conversation. I'd have my recorder running. I'd tell them that permission to call had been previously revoked and ask them why they are still calling the number.
I'd then write a nice polite, but unequivocal letter to them telling them the substance of the two calls and directing them to cease calling the number. Sending it CMRRR.
I'd repeat the second step every time they call again.
You need documentation of your withdrawal of permission and a few willful violations to go along with it before you can sue. Methodically and quietly go about collecting it.