Forced to buy a 2nd hand laptop

I bought a Mecer Laptop at Game Springs Mall on the 07th of June and it didn’t function properly as it was always asking me to reload windows. Unfortunately I could not take it back within 7 days as I was at work. I was only able to take it back on the 15th of June and I was told that it will be booked in for repairs. I informed the Managers at Game Springs Mall by the name of Nurse and Herold that I was no longer interested in that laptop as I bought it for work purpose and I was not going to pay for something that has been repaired while it supposed to be new. I then bought another laptop (HP) at the same Game Springs Mall. On the return receipt was I specifically asked the customer service agent to specify that I was no longer interested in that 2nd hand laptop. Now game Springs Mall is pestering me about the collection of the repaired laptop. Kindly note that I have already bought another laptop at the same Game store and I therefore would like for my money to be refunded back to my Game Store account.

I cannot be forced to pay for a second hand laptop which is supposed to be new. So please can my account be credited with the Mecer laptop money because I will not collect it.