False information provided

I just received a call from one of the agents. She called in regarding Vodacom and when I asked how much is the amount that I owed? she gave me a high amount than what I actually awed and i also explained why I stopped paying, as my previous number was reflecting someone's name than mine. Lastly she was too quick to send me banking details to pay and I'm still waiting for the last payment that I made to Vodacom as she said she doesn't have that information with her. As they never provided to them and that my file was handed to them on Sunday. What kind of a legal company is this that accepts incomplete documents and false amount then try to take action without making their investigations? Feel free to get hold of me again with full information to answer all of my questions correctly the R6k asked it's not the amount that I owed Vodacom .