Anu Solar — Solar tank leaked

I had purchased Anu solar water heater 200 LPD FPC. The tank is leaking and after lot of research gmcalled the service, instead sales person came and complained that the dealer is closed. The sales pe son also took 400 rupees without bill for visiting. Hence need to pay 3500. The product is still under warranty but still charging me money. This is absolute fraud, cheaters. Pls assist