fraud on warranty

i bought a bluetooth of boat on 2 december 2025 on 25 august2026 both the bud stop working no voice i claimed a warranty mail that was for 1 year as per invoice .on 2sept of recevied a meaaage from boat serivce that ear piece does not ha net so they rejected ma claim . while purchasing from a shop there in no dicalimer about warranty. A nd i want to knoe if there is technical issue of ear piece how they can reject by giving reason of not . i also contacted to there customer care number but they refuse to correct the issue by telling i need to check there web page before purchasing. there is no booklet with thw packed product i am suffering from all of this