Bill paid yet still sending statement to pay!

I had scans done on 10 March 2015, my medical aid paid their part, and then my daughter paid the balance 3 days later, in person, after I received an sms stating how much was due. <br> <br> A month later, I received a call to ask for payment, then a few days later, a statement requesting payment came by post. Today, by post, I received yet another statement from their accounts department, now showing I'm 60 days overdue!!<br> <br> My daughter and I personally went to pay the outstanding amount in full, right at their offices at Kuilsriver Hospital, 3 days after the scans were done, on 13 March 2015. It was paid via debit card, and the time was just before 11am, and we were attended to by Alicia who processed the payment and gave us the receipt, and the payment also reflects on my daughters bank statement.<br> <br> Now if we physically go in to make payment right there where it the scans were done, how on earth can they mess this up??? Especially after my last email sent to them detailing when and where to look for the payment, following the phone call we received a month later....<br> <br> <br> How *********** can you get???