@Filboxz 

I got somewhat same instance but I was the one that entered the correct voucher code. As I investigate, the customer has enabled his autofill and every time he was entering the code the browser (chrome) recommend old vouchers codes but eventually he was entering the wrong code for atleast 2mins and comes forward for inquery and help. 

but its a great if we can input our own number into the code like we can have a 2 digit (customize) + random number or suffix like random number + 2 digit just to have some identification on the voucher type (1hr, 1 day, etc) or where it came (01) code for store 1 or (08) store 8, etc.

Regards,