Misrepresentation and CPA Non-Compliance

I bought a firm mattress from Boksburg. The mattress advertised online was not available for testing, but we tested a mattress that I was told is similar in comfort. But when I tested it at home, it was very hard and not as comfortable as tested it in the store. I did not purchase a mattress cover, but put my own cover and sheet on it. I was told they cannot replace it due to the fact that I did not buy a mattress protector. I feel I was misled about the similarity of the bed. If I wanted to exchange i have to pay the delivery cost and the admin fee of R1000