MiX Telematics - Mix telematics incompentency

This company's accounts is the worst I have come to deal with. You give them 2 months notice and follow up on email and contact them directly to change banking details and they still cannot get this right. I have tried several times and have several reference numbers but they caused return debit charges due to not debiting from the correct account and then threaten you to still pay them. The return debits costs more than their debit order. I have tried to contact the managers to no avail. Then when you eventually tell them to remove their stuff from your vehicle, you are the bad guy and have to pay the price for this. What do you expect me to do? You guys are useless beyond compare!