Refund not processed - lost items

I purchased a few items which did not fit and arranged for the courier to collect it last week, Tuesday. After many calls and emails no one has bothered to refund me. Their excuse is that the item has been lost and they are trying to locate it. I was informed about this after i made numerous calls. When i requested to speak to a manager, I was put on hold. No one cares to call you back regarding any feedback. The service is pathetic. Each time you call the call centre, you have to repeat your query ten times to get the same feedback you heard previously. Nothing gets done !