Pathetic and disappointing service.

I regularly shop at Traders Warehouse. Until recently, end of September I bought goods at Claremont and Ottery branch. I went back after the 14 days to exchange the good and was told that I could not get a refund but they are happy to exchange the goods for something else. I was comfortable with that and shopped around but could not find anything to replace the goods. I asked the cashier at Ottery branch if I could get a "IoU" slip or voucher of some sort as I couldnt find anything at the time and she told me that as long as I have the slip and the tags are on they will exchange for something else. Twice thereafter I went back to the shop and couldnt find anything. Last week Saturday I was in Claremont and found a few things at Claremont branch. When I got to the till the cashier said they will not take it back as its too far along after I bought it. I told her what the cashier at Ottery told me but she refused. I then went back today, 19th November to the Ottery branch, found a few items, explained to the cashier and then the manager was called who then refused to exchange the goods. She then told me that nobody there would have told me that and it could have been the previous staff members who are no longer there. At the end of the day I did not suck this info out of my thumb, the items are still in the shop, tags are on and slip provided. Customer services has really gone down the drain because then the staff should have been trained and it has nothing to do with me that the previous staff members now gone advised me of such a process. I am livid at the waste of my time and the level of service received. If I knew this would be an issue I would have taken anything else to exchange the goods. Pathetic!