ACCOUNTS DEPARTMENT INCOMPETENCE

Despite the fact that my account is settled, I keep getting invoiced! The one payment was paid on the 24th January and it's still showing as unpaid, despite the fact that I have emailed payment confirmation and also gone to see accounts in person at Vergelegen Mediclinic to show them the payment confirmation. The second is an amount that has been duplicated (within a minute of each other), which both the account department and accounts at Mediclinic find odd. They were going to "investigate", but still I have received a "90 day" reminder and also an SMS sent yesterday. This is harassment! What on earth is wrong with these people?