Refund in full refused.

Extremely unsatisfied with the experience at Foschini Cape Gate. I bought 5 items of clothes on 15/02/2020 and returned 2 items on 22/02/2020. I arrived at the store at 09:20 to be told how I could not get my refund in full due to the sale it was on and the discount I got from the rewards card. The manager on duty did not understand what to do and phoned a manager on leave who informed him I can get more but not the full amount. Not sure what is worse, manager on duty not understanding the process or not getting my full refund. At 10:20 I left the store since no one could help me futher. There are 4 numbers of Operations Managers in the store and not 1 of them answered my call. Not what I expected from a so-called top retailer.