What an inconvenience

I purchased a voucher online which they said I receive instantly. I still haven't received the voucher. It's my son's birthday I'm at the store with him, with all his chosen toys. I still haven't received the voucher. When I call customer care they tell me there is nothing I can do. I must wait and they can't give me an estimated time. Now I have to tell a four year old that we cannot buy his toys on his birthday