Hi there @mungur Are you paying in full or getting a loan ?. you can only have 1 loan for a phone every 6 months through ratesetter. If your paying in full, try deleting all your credit/debit card details,and also try using another browser if possible as that can help to resolve things. If you are using the mobile site https://giffgaff.com/mobile also try using the full site,here http://giffgaff.com
Please also check out the link below and take a look at a great guide which may help you further,cheers.