Im trying to buy something online for the first time but their asking for my security number which isnt on there (believe me ive checked next to the signiture it isnt there) and everywhere online says its there but it isnt, please help.
The code is normally shown as the last three digits on the back of the card (on, or next to, the signature strip). If you've found a longer number, simply ignore everything except the last three digits. If that doesn't help, please tell us what type of car you're trying to use. (Debit card? Credit card? Issuer?).
If it's a Halifax Young Saver account the only type of card which can be issued is a cash card, not a debit card. So it can be used to withdraw cash but not to directly pay for purchases (either in store or online).
The same seems to apply to other 'Young Saver' accounts, such as those operated by Lloyds and Metro Bank.
Lloyds (so I guess other banks as well) offer two kinds of cards for young people's accounts. One is a fully fledged Visa Debit card, the other is what they call a "Cashpoint Card" and is only suitable for withdrawing money from an ATM.
Santander provide a Visa debit card for 11 - 18 year old that can be used for online shopping.
Any child can make a simple shopping contract - buying goods for cash or equivalent, which a debit card is. Buying on credit is a different matter.