Tesco Vodaphone e vounchers

MaximUK

I hope someone can help me as I am really confused.

I purchased a £10 e voucher from tescos to top up a PAYT vodaphone mobile.

What I got back was the normal till receipt for the other shopping together with a bar code printed at the bottom. It says Vodaphone e vouncher above it, but there are no codes or anything like I was expecting, just this bar code. It does have a 13 digit number under it but it is nothing like the 12 digit codes all the web sites I have visited seem to show for e vouchers. It also looks nothing like the e voucher shown on the booklet you can get from Tesco about e vouchers.

Does anyone have any idea what I have bought and how I am supposed to use it to top up the phone?

Thanks