Constant calls from them

I get at least 6 to 8 calls a day from these folks wanting to lower my interest rate. It is always a spoofing number from my area code and the first three digits of my phone number. How do I stop these idiots?  I tell to take me off their list and they hang up. Now I just don’t answer. Today they called 8:00 am which was first. Their calls usually start at 9:00 am.