Unresolved account issue

I went for blood tests at Arwyp medical centre at a branch of Lancet Laboratories in October 2014. My medial aid did not cover all the costs and I acknowledged that I would pay the shortfall on receipt of the bill. In April 2015 I made the payment of approximately R1448 or thereabouts using the \easy pay"system with account numbers provided by Lancet on the invoice. This is when my hell started. The payment could not be traced after I had provided Lancet with all relevant details. I then started receiving threatening sms's from a company ITC BA who acts on behalf of Lancet. Subsequent to this my wife in the interim on two different occasions sent Lancet the proof of payment (25/5/2015 &19/06/2015). The last POP was sent directly to an employee "