TOOK MORE THAN DOUBLE OUT OF MY ACCOUNT AND CONTRACT IS ONLY R199PM

So I have a contract with Telkom for over 2 years now, a ****le which is R199 pm...WHY FOR THIS MONTH DiD YOU TAKE OVER R400 out of my account? For what WHY? PLEASE GET BACK TO ME AND EXPLAIN! AND DO A REFUND OR KEEP IT AS A CREDIT IN THE ACCOUNT FOR THE NEXT MONTH...YOU PEOPLE ARE PATHETIC MAN! UNNECESSARY DRAMA