Tanishq — gold chain broken issue

Address: New Delhi, Delhi, 110088

A gold chain which is purchased from tanishq pitampura new delhi has been broken two times respectively even without usage. Same has been addressed to showroom. The representative has given the assurance and further repair the same by inhouse team however yesterday it broke again. The total weight of chain is 11 gm (Approx) but it is really not acceptable like tanishq brand.
Please let me know the way forward of the same.