It almost makes you regret uni, doesn't it! I have been in the exact same situation and still am. I have found that usually the people on the phone at the general customer service number are so unhelpful it is untrue! I was on the phone to 45 mintues whilst I was passed back and forth adn told that no one could help me at one bank. Then they finally gave me another number to call. By this point I was in such a state I was crying and the first thing the man I spoke to said was 'don't worry. I will help you so please calm down'.
They will eventually help you, I think they have to by law. Unfortunatly it is a real battle. First of all, I would go and see your bank manager, face to face. Be hounest, explain what has happened and he will probably be very helpful or will at least provide you with some advice on what to do. Good luck.