Non-stop spam calling.

Very irritating business. They keep on calling non-stop. After you decline their call they call back IMMEDIATELY, not even giving you enough time to put down the phone. Usually when someone declines a call it means they don't want to talk to you or can't talk this company takes it as a challenge. I have also told them multiple times I am not interested, I have blocked their number numerous times and I am registered on the DMASA do not call list, but still they keep calling without me giving my consent.