HDFC Bank — offering loan

Not sure why... I have already informed that i m not interested in any of the loan... But evey day i received call from hdfc offering it... I have asked them to block my number in there system but still no response... And when i tried to call to there customer care number, call was on hold for 5 mins and then got disconnected... It's like i can't tell what i want and they will keep on calling me for the loan offers...