Fake calls and messages are coming for loan recovery

I have never taken a loan till now. It's been a month since I took a J SIM after coming to Jammu, but since then I have been receiving messages to repay the loan and about 20 calls a day. However, no one has talked to me directly to explain their side; only the computer talks and they tell their side. No one listens to me. The SIM was probably previously owned by someone who took a loan, but the company people keep calling and messaging me, troubling me a lot.