FNB Vouchers- A waste

I purchased a Checkers voucher of R250 on my FNB App. I received Checkers Wicode as SMS. But when try to use the Checkers Wicode it doesn't work and Checkers advised I need to find out from FNB. I tried to call FNB for no avail, I was kept on phone call for ever and no assistance there. If the vouchers is not used the money R250 should be refunded to my account. But till now nothing in my account. FNB is pathetic. I need an answer why my account was refunded R250 for the voucher which was failed and expired.