AVON are such ******

I've been an Avon Rep for the passed few years. Last month I made a payment for an order placed at the end of the month. I sent POP and was told the payment will be allocated. Payment was made on the 4th, on the 15th I was charged R50 for late payment even though I sent my POP and was told it has been allocated. I keep emailing about this and am getting no response. Noe I'm losing credibility and customers because my order is being held for a R50 i do not owe. Disgusting, greedy behaviour!!