Bad debt in the past?
If that's the issue, there is every chance it has affected your credit rating, now you will be stuck with it like a dark shadow for 7 years from the default, providing you have cleared the debt up? If there is still debt outstanding you basically don't have a leg to stand on at all, you need to clear that up before people will lend to you again, as your credit history is in default. All banks and finance agencies will do a credit check on you before unsecured debt of a credit card is issued.
You can actually obtain a copy of your credit history, for a fee.