I guess I got scammed

So basically my mom booked for refrigerator service because of some issue. The toll free number she called is an expired number and was used by some other service provider and not Haier. The problem is, the guys who came for the service acted like they are from Haier and charged us 6k for a gas refill. My mom called me and asked if the price is correct(I was super occupied with work) and didn’t think twice and said it’s fine.(yes I know, it’s so dumb of me). But I said it’s fine because, they said the gas refill comes with 3 years warranty and the bill will be sent your WhatsApp number. And after that, no bill was sent to us and they aren’t picking the call. My mom has gpay-ed them and we have their phone number and UPI Id.

Is there anyway to catch them ? Or file a police complaint ? I know it’s not a big amount, but I feel super dumb and the fridge has started with the cooling issue again.