Disgusting harassment from Edgars regarding a loyal customer!

I wish to make a complaint against Edgars. I am a loyal customer who pays his accounts every time. Now I am being harassed by the accounts department as I am a little bit behind payment for this month but it is a 6 month account! Every month I have given more than the amount owed! This is why it is essential if not a major inconvenience to keep pathetic quality slips that do not even last a month with out the ink disappearing. I paid last on the 4th of August and actually the slip show I paid my account to full as I was shown a -38.44 for the amount still outstanding. What is wrong with their finance department I demand a break down of everything I have paid up to now! This to be is absolutely disgusting service and a slap in the face of a extremely loyal customer.