HDFC Bank — Repeated calls about personal loans

Every week i get calls, asking if I'm interested in HDFC's personal loans. I tell no every time. I have received calls more than 50 times. First of all, I don't even have an account there. How do you have my contact details? Im fed up of these calls. Do you not keep a record of who has said no to these calls. Next time, I get call, I'm forwarding it to the cyber cell department.