Bad customer service

I've bought tiles from Italtile Northgate in Cape Town two years ago without collecting it, that's my fault. Two months ago I attempted to collect the tiles but was told that it was collected by 'someone' within a month of the purchase. Now my question is, how is that even possible without the paid invoice? I spoke to Donovan while I was in the store and when following-up. They are trying to locate the documentation (signatures and registration numbers) related to the collection. There seems to be no urgency to resolve this issue, neither was I offered a refund.