Unauthorised deduction off my bank account.

I have been a Cartrack customer for some years, Earlier this month, in addition to the monthly payment ,which they deduct directly from my bank account, they deducted an additional amount of R 117.72. Via all their communication channels, telephone, webchat, emails to client services, emails to accounts department, I have enquired what this additional amount is for, AND who approved it to be taken off my bank account. I am getting no responses, apart from "it has been escalated"!