The ability to 'Pay Now'
'Pay Now' should be very easy to find and easy to execute. Despite searching your ever increasing list of Q&As, I could not find the 'Pay Now' facility. It just didn't appear within my portal. As such, I had to resort to help via a customer support engineer - Saikiran Rekulakunta|, Azure Subscription Management Support - to get the matter sorted out. Saikiran was excellent.