Boat life style - My Product in waranty but company denied to provide replacement and said silly reason

Respected sir/madam, I purchased boat wave beat smart watch on **-**-**** and the warranty period of the smart watch is * year and now in warranty. Said smart watch was not working for last one week so i file a warranty claim. Immediately they arrange service partner for pick up the said watch. He came and thoroughly verified my watch they not found any physical damage at the time of pickup. At the time of handing over my watch, watch has no scratch and defect, on *th October, **** I was received a mail from Boat life style along with picture they did something in my watch strap and denied to service my watch and returned my watch through courier, I was not received and return the same to boat life style yesterday (**.**.****) they send one video that was created by boat for denying my claim and telling un logical reason and rejection, they poured something in strap edge and they find reason for rejecting warranty. My issues is watch has not working I am not claim anything for strap. So I humbly request you to take necessary action and get back watch with working condition or get back my refund amount earlier as possible