extremely bad attitude

I went to Woolworths Sandton , on Saturday 05/12/15 at around 13:00pm I went there to change a witchery clutch bag that I had bought for my sisters' matric dance however i was taking it back to the store because we ended up not using the bag I bought her another one. when I arrived at customer service I was told that they will not take the bag because its dirty it had a black mark inside it means I was using it. I said to this lady how can you accuse me of using the bag when we never even used it and the reason I was bringing it back was because we don't need it anymore. I even mentioned to them that when I bought this bag it was on display what if it was dirty because it was on display but they still refused to take it. I than called the manage and told him everything he referred the matter to somebody higher who advised that they take the bag and give me a voucher .I went back to customer service for the voucher by they gave me pathetic attitude again .I'm very disappointed with this kind of service I received and the accusations I was also treated like a fool after spending over an hour in the store trying to be helped but I was sent from pillar to post instead.