billing unauthorized amount

I joined rain on the 2nd of December and activated with R1 as per the agent who called me. I gave a debit date for the last day of the month but to my surprise, they tried debiting an amount of R445 on the 15th of December, I made several attempts to call them or get them to call me but the two agents that I spoke to could not give an answer what that amount was for, I don't understand how this provider operates but it is way ********* and comes across as ***** since no customer agent gets back to you promptly with a query, but is quick to call to sign you up. My internet access has been cut off and I still have not received a call from an agent to explain why they tried to debit on a date we did not agree on. I need nternet access for the kind of work that I do and right now I am frustrated ,quite annoyed frankly that it hasnt even been a month with the provider but already I am having sunch issues