Unacceptable inconvenience

After days of failed attempts to contact cell c to debit my account I eventually visited a store trying to pay the outstanding amount owed for my contract I was given a statement with the total outstanding amount on it and was told to make a payment once I have done that I was instructed to send the proof of payment to the lady who assisted me from the cell c branch in Cresta mall a few days after that I received a call confirming that my payment was received and account is no longer in arrears cell c has now gone ahead and stated on my credit report that I have not paid them and the outstanding amount is now double causing my credit score to drop by 22 points and now because of this matter I can not be approved for the vehicle I intended to purchase hence the reason I went out of my way to ensure I pay cell c and all other creditors in full so that this does not happen yet cell c is the only institution that makes a negative mark on my credit report after receiving their payment i have had endless issue with cell c from