Poor billing process

Had an operation on 18/11/2024, Netcare did not send me an invoice until 10/01/2025. Got a letter today with a courteous reminder that the balance is outstanding. Amount would have been paid within 30 days of invoice if your accounts department knew what they were doing. Netcare can wait now until my gap cover pays. Emails also go unanswered when trying to get hold of the accounts department.