Pathetic service

National Security invoices/statements who double checks when they send the client incorrect information yet demands money and wants to suspend the services. I paid my account upto date yet they invoice and do not reflect payments made on an account. So whose fault is it. They take long to respond they debit your account when they feel like it. No statement. Incorrect amounts. No explanation. Since January I've been emailing them no response yet they want to terminate my services based on what grounds