The manufacturer of my washing machine made an appointment with A&E to have a technician diagnose a problem with the washer (at the manufacturer's expense). A&E's idea of an "appointment" is that they will come between 8 AM and 5 PM. We rescheduled the appointed day to one when someone would be able to be home all day--one week after the initial "appointment."
After diagnosing the problem, the technician told me what the charge would be. I told him that the manufacturer was paying the charge. He told me that it would be easier for him to cancel the appointment after it happened rather than track down the billing glitch with the office. Easier for him, perhaps, but more difficult for me. When I followed up with the manufacturer to arrange for repair, A&E had no record of the visit. When arranging to have the part installed, I naturally asked for another service provider.