MBD Call harassment to incorrect client

MBD Credit Solutions have called my cell number over 100 times in the last month looking for someone called Roshila Singh. I know no one by this name and several times, have asked to speak to a supervisor and have explained, given my ID Number and they faithfully promise to remove my number and not contact me again - and guess what??? I get called ten times again the same day!!!!! I am at my wits end!! How do I get them to stop calling me?