Bajaj Finserv — getting more calls to take loan

The mistake that I did is that, I have taken consumer product through Bajaj Finserv 0% interest very long back. Still they are calling to take loan still I have asked them to de-register.

Please stop send messages and stop calling. If we require a loan we will contact you. Please behave like matured and stop calling or messaging.
It would be better to put one code to de-register customers by themselves.