Fraud by a shop

I bought a LPG regulator in September 2023 from a shop. The shop owner told me that it has a warranty of 1 year and I being foolish enough, didn't ask him for a bill. After that in May 2024, the regulator started leaking gas. I called the shop guy and he said the regulator needs to be replaced. He didn't agree that the regulator has warranty. I couldn't prove since I had no bill. So, I went ahead with buying a new regulator with the bill and warranty mentioned on it. Now 2nd Jan, the new regulator started leaking. I made a phone call to the shop guy, he said he will visit at night to check as his shop partner has gone to hometown. It has been 2 days and the guy didn't visit. I went to the shop again with the regulator along with the bill to get it replaced. Had a heated argument then he said he will visit tonight. He hasn't visited to check the issue yet I won't accept losing my money to a fraudster. I am planning to register a grievance on consumer helpline. Please let me know if something better can be done in this case.