Worst Service ever Netstar!

Netstar service is very poor and irritating. I made a payment of R576.85 which was due last month. I sent the proof of payment to them aswell however they sent me a statement which says my account is handed over to collections and still shows the amount as outstanding, when I call the call Centre they answer the phone and leave a person on hold forever, I sent an email however no one is getting back to me. This is the worst service I ever received in my life