Accounts department is a Disgrace

Very poor service from Cartrack accounts department, no one even knows what is going on, one hand does not speak to the other hand, they keep telling me that i must pay extra and even though i have paid they still on my case, i have given them proof of payment and i also asked them to cancel it but no one sees that, this service is a disgrace. If i had the extra money i would cancel with cartrack, this is not the first time that they have done this to me.