How to deal with the extremely annoying spam calls and WhatsApp messages from Bajaj Finance?

I have been receiving 4-5 calls every day from Bajaj Finance for the past 3 years. They call daily about personal loans and overdraft facilities, even though I have never applied for a loan nor shown any interest. I worked for only 5 months in their sister company 3 years ago. Since then, these disturbing calls started. I have told them many times clearly that "I am no longer a salaried person, I don't want any loan," but despite this, their spam calls have not stopped. The current situation is: Daily Spam Calls: I get 5-6 calls every day. I use Truecaller service which automatically cuts about 5 of their calls daily as spam. WhatsApp Messages Without Permission: Now they are also messaging me on WhatsApp without my permission. Violation of Data Privacy (Data Sharing): Earlier, calls came from the company's official/system numbers, but now it seems they have shared my and others' personal contact numbers with their private agents/DSAs. Different agents are now calling and messaging me on WhatsApp without my consent. It seems these people have no fear of any government law or court. When I don't even want a loan, why am I being harassed so much every day? I am now thinking of filing a case against them in the District Court. Is anyone else facing the same problem? If anyone has a solid solution or knows how to take legal action, please share in the comments.