After paying statement get sms to pay again.

I received a call that we have outstanding accounts and a sms that I owe an account, I paid on 05/10/2015 the amount of R165.10 and forward the proof of payment. I received a call from the collections department on the 6th of October 2015, after I have spelled my email the they still got it wrong. I confirmed my email again and said I have paid the day before from STD and she said the amount is not reflecting in the Nedbank account which I said to her it will only show in 3 days but did sent proof of payment.. Now today we receive an sms again: Payment reminder R200.05 due on your Lancet account today. ..... Balance out R34.92-<br> <br> So what is outstanding and why if I paid the amount as per statement? This is really misleading that you do not get a statement and your receive an sms now know what you owe, so everyone sending met Sm's I must pay. As per the email from SCS Collections I have paid the full amount. As per Lancet our account was settled in full, so I must get sms messages saying I owe money which I paid according to the statement and my proof of payment.