Useless

I have been making payment towards my account and when I call in to confirm if the payment has been received they can not find it even tho I am using the details they have given me. I have paid last month and they still can not find the payment but are sending me threatening emails ..spoke to numerous people karabo(manager) and agents named thando and nomsa who couldn't help. What is the company there for when they are so useless. I am writing on here hoping to get some help from them but it seems they taking the money for themselves and leaving us with more debt and stress.