Bad service

I have visited the Edgar's centurion Mall over the weekend. I had 3 discount vouchers . I was told I can't use discount vouchers on reduced items. I did 2 transactions which is one for reduced item , on this one i know i don't qualify to use a voucher as items are already reduced and the other transaction was for normal priced items. When I want to use the R200 voucher I was told I can't as I need to use it at Edgars sports wear however it does illustrate that voucher could be used in Edgars store . This voucher will expiry the 30th and is an amount of R200. I need this voucher please.