Reliance Digital — Aqua guard issue within 3months

I have purchased an aqua guard from Reliance digital on 25th March 2021, within few days it started to create problem and in 3 months it stopped working. We have required the store staffs to help us with this as it is not even 6 months we have purchased the product. The staffs are saying they cannot do anything. This is ridiculous that the company is not taking any responsibility and has sold a defected product. They are ignoring our requests and are saying I have to purchase the filters from the company.