My debit card

One day magicly my card stopped working, great. I find out by trying to buy something on steamgames.com and having my card declined, apparently my card number was wrong, which is wasnt. I thought it might have just been steam so I tried on google play and it didnt work and it had the same problem even though I had my card in my hand and looking at it, thanks to this my black Friday online shopping was nothing, I tried to send a message to FNB complaint centre but I dont axacly have my id number on me at all times. My account balance is fine I have enough to pay for it including vat and have plenty left over but now it doesnt matter because FNB messed it up, I understand that it was black Friday and everyone is using there credit cards and all that but now its Saturday and it isnt working. Im considering movingbto a different copmony because of when I needed a new card there was bad service and the person working at the counter was just a *****. I also had to wait 2 more weeks than promised because we were not propoly informed.