Call them back. Tell them to stop calling or you will report them to the Bureau of investigation. If they dont stop then, than report them. They can not keep calling you once you have told them to stop. It's harassment and they can be brought up on charges if reported enough.
This man from india cause once or twice a month always asking for someone with the name Jim. they have called from other numbers as well as this one and there's nothing that the Federal Trade Commission the FCC or the PUC. They always call from a different number so I always check numbers online just to see if others have had the same problems. What was is ironic they always call for Jim and the always call on my cell phone. So I just told him that he's delusional and narcissisticand is mentally deranged and he needs to see a psychiatrist and then he hung up and hasn't called back for a while.