Terrible service

Disappointing service. I purchased an item online and was not happy with it. I returned the item to the Cornubia store like asked to, and was told that I will receive my refund within five working days. It's more than six weeks later and after several calls and emails, i'm still waiting for a refund/voucher? Every time I call, the response is that they cannot explain the reason for the delay but will escalate the query.