Useless accounts department

Fidelity ADT accounts department is the most useless rep ever, they send statements every month they don’t even bother checking the payments that are made. They just ballon the statement amount and ignore payments. Even after I have told them millions time to allocate the payments they still fail I have therefore decided I will never make any further payments until they get their house in order and once they are done they must terminate my contract I will source other best suited suppliers