Bajaj Finserv — constant calls every day for loans

I have taken couple of flexi LOANs from bajaj finserv and like clock work I am getting 4-5 calls every single day. It is so irritating that I have stopped taking calls from unknown numbers from last 2 years. I have requested the agents calling 1000 times to remove my number from their database as I am not interested in LOANs. All they do is apologize and with an assurance that my number has been removed. But like a shameless bunch the calls continue next day as well. It has been tormenting me and I feel like I have committed grave sin by taking LOAN from Bajaj FInance. How can a company be so shameless that it harasses its own customers every day. I am unable to find out a way to stop this harrasement and unfortunately I am not able to change my number as well as it is linked to multiple important locations. If someone can help me out of this mess I will be really helpful