Cell C - Harassing you even if you did make a payment

Cell C is the company that harasses a person even if you did make payment, I made a payment on Saturday, received a sms confirming that the payment was received.... but they keep on phoning me to make a payment arrangement.

I have asked on 3 different occasions to phone me after 3 and they do not do that. During the course of my 2nd call I have said that I will call in the new month to set up the debit order again, but they do not make the notes on the system.