Itunes & card details help please (uk)?

i just got an ipod for my birthday and im trying to sign up to itunes & im getting so stressed out cause my debit card (solo, maestro, natwest) & it lets me use it on paypal & ebay etc.. plus all other sites, but now its saying please enter correct information and my card is declined, which ALL my information entered is correct, its just being extremely annoying & dont understand it :@