CELL C CONTRACT ****

I HAVE A WIFI CONTRACT WITH CELL C FOR 24 MONTHS, LAST MONTH IN JANUARY WAS SUPPOSED TO BE MY LAST PAYMENT AND BENEFITS, THEY HAVE BEEN CALLING TO CHECK IF I WANT TO UPGRADE THEN I SAID NO AM NOT GONNA CONTINUE WITH THE CONTRACT, TO MY SURPRISE THEY WILL STILL DEBIT MY ACCOUNT EVEN IF THE CONTRACT ENDED, JUST BECAUSE I DIDN'T CALL IN TO CANCEL IT AND NOBODY ADVISED ME ABOUT THAT PROCESS, I DID NOT KNOW ABOUT ALL OF THAT, NOW MY QUESTION IS 'WHAT IS 24 MONTHS CONTRACT I SIGNED FOR? I DIDN'T SIGN FOR 26 MONTHS CONTRACT, I FEEL LIKE CELL C IS REAPING US OFF, NOW I ONLY GOT HALF OF MY BENEFITS AND AM GOING TO PAY A WHOLE R199 FOR ****, I AM VERY UPSET WITH CELL C AND I DON'T WANT ANYMORE CONTRACTS WITH THEM, THEY VERY UNPROFESSIONAL