I called every five minutes or so, and each time was told that it was on its way. Finally, after twenty minutes, the operator confessed that she didn't have a taxi free to send us. I hung up, and eventually we scrabbled around for another number, and managed to get there in time - but not before I'd asked her "Are you aware that we're going to my grandfather's funeral?".
Edit; Few points.
We were told that the taxi would be there within three to five minutes at first, and the second taxi firm made it in that time. That's also a perfectly normal timeframe for here.
I mentioned my grandfather's funeral once we'd already accepted that we'd need to call someone else; I didn't expect her to magically find a taxi.
Thirdly, I was just sixteen, and very close to my grandfather; yes, I did learn from it.