Anytime you let a match go 7-7 and let your opponent to the table it's not unexpected that you may lose. Take care of your end of it and things like this won't happen.
In answer to your thread title; I've lost one hill-hill match in my life (that I remember).
P.S. Nobody got "robbed". Nobody had anything coming to them, thus it couldn't have been taken away.
Like Martin Scorsese said in the intro to TCOM ... a player can shoot eight trick shots in a row (paraphrasing now) but if the nine which is the cheese ball goes in his opponent wins.
Pretty sure this type of shot is responsible for hearing 'really?' at this point in the match.
Do not touch your cue until the flush of anger has left you drained and calmed and spent. A barely audible mix of sobbing and laughing is acceptable in these situations.
Try to avoid the pressure cooker blow off scream followed up by a Tasmanian Devil spinout where you swing your cue at any pinata you see.
This kind of outcome is indicative of confirmation bias which lets the fluke shots eat you up when they happen against you. Have you ever lucked one in? It works both ways!
The truth is if he is that much better than him you cant blame it on luck in the hill hill. It should have never come to that. I am sure the better player did not play well during the rest of the match or it would not have been hill hill unless the winner was in fact a better player than indicated.