POOR POOR POOR POOR SERVICE - DIS-CHEM

We have been ordering our chronic medication medication for delivery from Dis-Chem for a while. We suddenly got an email from Chrisna Trollip in their accounts department saying we owe them over R1000. We complained because the person delivering the medication never ever asked for a co-payment and always gave the the medication. We then paid the up the amount and used the reference as directed by Chrisna Trollip. She keeps sending emails asking for proof of payment. I will not send proof of payment because my bank charges for it. Can she not check her accounts for the correct reference as shared with her via email? Now she comes back and say we still owe a further amount. How Chrisna, when we don't even use Dis-Chem anymore because of YOUR POOR SERVICE!!!!!! I cant even escalate this to a more senior department because the information is not available. I HAVE NOW STOPPED BUYING FROM DISCHEM AND GET MY MEDS AND TOILETRIES AT CLICKS. YOU LOST ANOTHER CUSTOMER BUT I DONT SUPPOSE DISCHEM CARES. @ DIS-CHEM, WE DO NOT OWE YOU ANY MORE MONEY!!!!!!!!