By the sounds of things you have some bad credit marked against your name. It may be worthwhile getting a copy of your credit report. Be wary though as some online providers trap you into debit card agreements which are hard to escape again. If you look on the experian website their should be an address which you can use to request a copy of your credit report for £2.50. If someone has taken out credit in your name it is important to get this rectified as it will go against you for up to 7 years. if you live in an area with a good credit union and are employed then it may be worthwhile contacting them.