Impossible to schedule an appointment and no assistance

I share the same problem as many people I have read the reviews of. Impossible to schedule an appointment online to submit an application. We paid via credit card 5 weeks ago, spent many hours on phone calls, emails to the payment allocation department. The people at the call center keep saying that my payment has been escalated with the Finance department, (that was a month ago), but there is a backlog so we must just wait. They can't help further. Our visa is running out, and we will have to make arrangements to book a return flight soon if we can't submit our application for extension. It is very frustrating, when you try to plan everything correctly and in time, but get no assistance. Then I am asked to rate their services after the phone call...