Croma — Forced paying extra

Address:

Croma store, near chinar park kolkata

Hi, sir I have bought a headphone from of boat from croma stores in chinarpark kolkata on 22nd January 2022. On 10 th may one side of it stopped working. As it was under warranty they agreed to replace. But when I opted the same model which was to be replaced. They told me either I have to pay more, or choose lesser model as the price has increased . Sir why shall I pay more? It's under warranty, and is it my fault that their product is faulty? Instead of replacement I was forced to get some cheaper model . Is it fare or ethical ?