Bad services

My name is johannes motlhajoe account holder at ackermans card number ***,i normally pay my account by EFT so on the 1st Feb 2016 I paid R2500 by EFT and I was supposed to pay R40 only,because earlier last month I asked for credit increase but I was sent from pillar to post,they asked for 3months statements of which I sent maybe 6 of them daily but they still rejected me,So Monday 8February2016 I went to kuruman mall wanted to buy a cellphone and my card declined and said I have only 400 in my balance,head office was called but they said there is nothing they can do about it can someone explain how this happened because now I will never ever trust Ackermans