Voucher top up not working

[Anonymous]

I bought a £10 voucher to top up and went to top my phone up not 5 minutes after. When I put it in first time I accidentally hung up the call and it hasn't put the money on my phone. I then called the top up line again and put my voucher number in but it keeps saying that there is a problem? How do I fix this to put the top up on my phone so I have to call o2 themselves or go back to the shop?

[jonsie]

The occasional error does happen but in fact it is down to the seller of the voucher if there is an issue where the voucher shows as cancelled.