Incorrect Charges

I took in to the Vereneering Branch 4 empty cylinders for refill with LPG. Com month end I see an incorrect charge of R2600 for empty bottle deposit. I raised the issue with either *********** extremely lazy staff , 4 months down the line I am still to be refunded for the incorrect charge. they keep sending me round and round. at one time some guy introduced himself as my account manager, only to be replaced a month later by yet another one, and this new one now cannot be reached via email. SAD how this company treats small businesses.