The impression i had from the re-enactment, was that by telling ATC on a few occasions that they were low on fuel and also asking for priority they thought they had declared the equivalent of an emergency and thought that they were getting appropriate treatment, clearly this was lost in the way it was communicated.
The Captain did tell the F/O to declare an emergency on several occasions, only the F/Os version of declaring an emergency had been to ask for priority and advise that they were low on fuel.
Whilst ATC cant be blamed for Avianca not keeping an eye on the weather, and not demanding vectors to commence an approach, they certainly should have realised that if a jet has told them on numerous occasions that they are low on fuel, and about to run out of fuel, something cleary is wrong............... instead they vectored them up the creek.