I have a £5 promotional/free Zeek code, so I opened up a Zeek account and entered the code. On their site, it says that you only have 10 days to use up the code. I've been looking daily but there is nothing at all for £5 on their site. Am I allowed to buy a card on there, say for £15 and apply the £5 credit and pay the difference, or do you have to pay for the cards in Zeek credits only? Thank you.