Awful account administration / Account lockout

We recently became Sage Payroll customers. They recently cut off our service with no notice, alleging account arrears of 5 months when we enquired. This was 100% wrong as a debit order had been running since inception of the subscription - we are and always have been fully paid up. Slow to respond. We are locked out of payroll processing as month-end approaches, risking our employees' timely salary payments.