Bad service

My friend got me a pair of earrings as gift just about over a month ago. I've only worn them about twice however this morning I just discovered sum of the jewels has come out . I can only wear sterling silver and I expect the product to also be of a good quality. I understand your exchange and refund policy but in this case I'm returning a faulty item. I popped into your store at canal walk, the lady just went on about exchange policy and hygienic reasons, it was like I bought the item an wanted a different item. She just said no when I asked if she's going to replace it. No apology was done or anything and I don't think she was manager. I am very disappointed in the service I received. I have sent them message on Facebook still no response.