Why is a website not allowing me to make an online purchase?

I have a Debit Card which I'm sure can be used to buy things because I used my same Bank account to buy an app on my iPhone however, when I try to use this card and enter the details to buy a video, it says 'credit card fraud' error detected. I put all the details in correctly. The only thing is the website I asks for CREDIT card details but my card is a DEBIT card, does that matter?

Also, the website owner I assume is American because the video prices are given in US Dollars but I'm British so does it matter that I'm not paying with the same currency? I thought they should easily be able to convert the payments?

Many vendors don't accept debit cards for on-line purchases.

Of course it matters, it said No debit cards, how hard is that to understand?

Unless this is a Visa/Mastercard branded debit card, your debit card can't be used as a credit card. Even if so, there's a distinction and they might want a real credit card here.

A true bank issued debit card is usable all over the internet with few if any exceptions. If a gift type card then you are going to find even more trouble.

When you called the bank what did they tell you?

Because you are trying to use a debit card to buy something from a US website.

Many US websites do not even accept debit cards from the US, and even fewer would accept one from another country. To buy from many US websites, you need a real credit card, one that is not a debit card, a gift card, or a prepaid card. And even if you find a website that accepts debit cards, it might accept them only if they are from the website's own country. To buy from a website in the US without a card from the US, you could need a true credit card (not a debit card) even at a website that accepts debit cards from the US