Payment method declined

Hi, I'm having trouble trying to pay for something in iCloud. It says my payment method has declined, I have a visa debit card so click visa, even though it is the correct bank details, not expired, enough money in the bank, correct phone number (i tired 044, 44 and +44 area code) and I have also checked if I have any outstanding payments and I don't.

I haven't purchased anything in 18 months. I remember last year I tried to pay for an app and this didn't work although I didn't like the app enough to enquire. Now I'm trying to buy extra storage which is £0.79 a month and it isn't working.

I looked at a previous discussion and tried on my iPhone, through iTunes and here online to change the payment details, I have clicked 'none' and tried again but still hasn't worked. I'm not sure what else to do now, would it be my card has been blocked with iTunes or something, looking back at previous payments they were made with a different card and I haven't actually purchased that much (less than £10).

I have had this iPhone 5c for 18 months roughly and was originally contract but paid the rest off and I have had this debit card for a year if this info helps.

Maybe I'm missing something important out, I'm not sure. Any advice would be great thanks.