rude agents

I have never been so disrespected by a call center agent in my life, Lerato and her Manager Anna have the worst behavior and no telephone ethics, i have no idea how they work for an institution that collects money, i sent them proof of a payment that was made by Discovery for the only visit I had with " Dr Zimba" they refused to accept the proof saying that they have a second visit to which I have not been to this " Dr" for the second time, I asked Lerato to send me a statement showing that they have received this payment to which she refused to send to me, i asked her to contact Ampath requesting this proof as there should only be one account to Ampath and medical aid had paid but she came up with a second account to which I cannot be provided with proof of payment of the only account that I know, she started speaking as if I was her friend from the street corner saying " ai wena you do not want to listen" how on earth do you hire a person that speaks to clients in that manner and i had repeated that " remember your calls are recorded " she continued insulting me, then she ended the call in my ear, are you guys above the law that you can speak to people anyhow you please? I will be escalating this issue.