Solicited Calls

I am registered with the National Do Not Call Registry.  Over the last few months I have received a phone call from Card Member Services at least once a week offering me a lower interest rate on my credit card.  Each time I transfer to a live person and ask them to stop calling me.  They then hang up.  Today the representative said he was with the Qualifying Department and could not take me off the call list.  Then he asked me if I had a balance on credit cards over $5000.  I said no and he hung up.   I have no idea who this company is.  I have never authorized anyone to call me from my credit card companies.  Is there anyway you could put a stop to this?  Thank you.