Incorrect Debit Order For Several Months - Cannot Get It Rectified!!!!

I am extremely annoyed with the level of service I am experiencing at cartrack, I have called on several advising them to change my debit date since June last year. My debit date was set on the 25th of each month and now I experience irregular debit dates trying to debit my account on the 1sr,3rd,5th,7th of each month and this was NOT part of my agreement with you. I have called on several occasions to have it changed and I am still experiencing the same issue, I have occurred many bank charges due to this, Secondly my unit is not working and is now taking several weeks to rectify, should something happen to my car I wonder who is going to be responsible!! Please rectify this immediately.