Bad service

I app**** for a credit card which was approved I sent all relevent documents as well as the Agreement with credit limit etc... i was then sent an email to say my card will be delivered in 5-7 days. I called the call centre many times to check if they received my documents and each time I'm told they cannot find it! Today I'm told its declined and cannot give a reason. You approved my application I have all the correspondence I need feedback. Its really bad service. My reference number ***