Pathetic Pandora

I purchased a charm bracelet for my daughter's 21 birthday in June 2020 The bracelet has changed colour/tarnished. i took the bracelet to them at Eastgate. The sales person/manager refused to take it back and askeed us to clean it by soaking it in sunlight liquid for few hours. we tried this and the colour remained dull, copperish and tarnished. We took it again and still no assistance from Pandors in eastgate. is there someone out there with the same problem? they do not seem very keen to assist. What do we do from here???