There are normally no queues at the barriers so the fact that you had to wait and the barrier was up suggests the paymemt system had gone off line.
Also unless anyone knows different I don't think the airport has any means at the moment of charging the per minute fee as there is no number plate reader on the approach road or in the drop off area. Well none I can find and I have had a good look!
Hotel is outside the protected area for the ILS.
So is the multi story car park but the protected area is not the issue.