Over billing and rude consultants

I called into the cellc contracts department for being over billed and I spoke to a consultant by the name of Noxolo Mazibuko, she was very rude and refused to assist me in an orderly manner. She did not explain everything to me and she transferred my call without informing me that she will put me through to another consultant. I am utterly disappointed about the service and disrespect she indicated towards me.