Poor customer service

I am very dissatisfied with the service I received at MR price in Cleary park Port Elizabeth yesterday. I have vouchers to the value of R1400. I travelled to go buy a few items and stood in a long line to pay for them only to be told that "unfortunately we cant help you " when I asked why I was told that vouchers don't work since Saturday. Surely if this issue has been happening since the weekend it should be sorted on a Wednesday. So MR price has R1400 of mine and I cannot use it just because you are lazy to fix your systems????! When I asked when the issue will be resolved the manager told me she doesn't know. That is unacceptable and I would like someone to arrange a refund on those vouchers so that I can actually purchase the items I want to buy.!!