Billing/accounts department debiting every other day

I have an issue with cartrack accounts department as they keep on debiting my account on random days without my permission today is the 7th yet they still debiting which means I can't even keep money in my account as my account is being debited every other day our agreement was the 27th of every month but no they debit the 27th the 30th the 7th then again in the middle of the month like who even does that so many dates without my permission I'm very tired of this of the billing department can't stop this debiting of every now again I'll have to go to another tracking company that sticks to their agreement and not do what they want