Billing issues

Pathetic service and horrible experience, they double bill me all the time, when I call their customer service line they say I don't have a contract with them, I took it from telkom direct old mutual last year Feb, however they deduct every single month without fail, they don't even upload their number on Google because everytime you call them either drop the call, no answer or answer and hang up. I want to cancel, my contract says debit date is the last day of the month, however they do not deduct up until the 1st I even went to telkom at workshop to go pay was told to call customer care line.