Very poor client service

I got three vouchers from a company for Shoprite, when I went to the store to load these vouchers only one worked and the other two gave a error. I have been trying since Sunday to get this sorted and no one can help me. I don't understand, If I am a client in store and want to spend money I need to get assisted, but they just don't care. I am really not happy with this service and it must be the worst company I ever dealt with and with no customer care