Totalsports *****ing

Received a shirt as a gift, the shirt still had the tag and the price on. I didn't like the shirt and went to the Gateway Totalsports branch to exchange it. They said they would exchange it. The shirt I was exchanging was R129.99 and the shirt I chose to exchange it with was R349.00. Obviously I would have to pay the difference. When I went back to the till they refused to credit me the R129.99, saying the shirt was now on sale for R99,99! They wanted to keep the shirt and the difference of R30!! Basically *****ing R30.00!! The person who bought the shirt paid R129.99, that is what Totalsports received. To then get the shirt back and to keep R30.00 is unacceptable. I therefore was unable to exchange the shirt. Reminds me again why I don't shop at Totalsports