Never share number with IDFC agents

In an electronic appliance store one IDFC agent (they processes loan applications) asked my number for notifying offers. On insisting, I gave him my number. Since then, I have been receiving 2 calls everyday from IDFC. Most of them are robocalls. It is really annoying. I also turned the DND on from the site of IDFC, but still I am receiving calls. New day, new number. I will advise everyone not to share your contact details with these guys if you want peace.