Broken chain, poor communication & lack of service

I purchased a 9ct white gold chain from Hillcrest store at the end of Dec2014 only for pieces of the chain 2 start breaking off i returned the item 2 the store in early February. The item was sent 2 head office for assessment of which the blame was put on me & and a 50% discount on a future purchase was offered this was worthless to me as I have a very expensive item that is not repairable. After requesting a report from head office stating the cause of the chain breaking this was sent through to me where a exchange was now offered to me. After telephonic conversation with head office it was confirmed that the store was aware that I would be coming in 2 exchange the item. When I arrived at the store they did not have stock of any suitable chains, it was said that they would order stock and inform me when it arrives. 3 weeks later still no call from the store when i went into the store i was met with the statement \oh I was meant to call u"they had not ordered chains as they apparently had no authorisation of the exchange being allowed. The manager stated she was not willing to do an exchange even though head office gave this instruction . Will never step foot in a NWJ store again!"""