FNB Google voucher is ****ed up .

Hi, bought a R50 Google play voucher and could not load it . According to Google the information does not match there systems . I logged this twice before and not 1 call in return only 2 emails advising me that the code is valid . If I bought this from FNB and it does not work , who would be at fault . The department that deals with this is really ****ed up cakes .