This is all utter bollocks. Its bookable. Call the gold line. the flights need to be available so you'll need to do a search.
If you get the overseas line, hang up.
For those who don't have access to the Gold line, well - that's a pity.
For the chap looking to book BOG-CTG - that flight is ridiculously cheap - not sure why you would bother with Avios anyway.