bAD SERVICE - WRONG BILLING

i WAS CHARGE R399.00 FOR 5 DAYS, PROMISED I WILL PAY PRO RATA NEXT MONTH - WHEN I ASK THE PRORATE CHARGE I WAS TOLD I MUST PAY AGAIN r399.00. tHE AGENT JUST CANCEL YOUR CHAT AND DONT WANT TO ACKNOLEDGE ON WHAT WAS PROMISED - POOOOOOR SERVICE AND ******* - CHARGE YOU NOT CORRECT AND REFUSE TO ASSIST