No one ever calls me *****

I have just received a call from a consultant by the name of Ntombi who I doubt is even a debt collector for NBS requesting a make payment for my cell c account with them. When I disputed the amount she gave me attitude called me a ***** and carried on babling on the phone while I hung up. I am beyond shocked and disgusted by the attitude I have been given by this Company even though it was my first time dealing with them.