Vodacom bad service

Very disappointed with vodacom they keep our personal information to **** and deduct our money with out permision, I had a contract with them which ended last year then I canceled it last year.i was paying R155pm, this month vodacom debited R410 out of nowhere, I went to vodacom shop in Westgate to escalate but they where unable to help me and gave me a number to call *** and no one picks up the phone, I want to know why vodacom debited R410 when contract has ended and cancelled