That looks horrendous, maybe there is a slight bow in the tile but still, looking at that I’d say they didn’t even bother checking the walls with a straight edge and just followed the walls with a 6mm serration ......lips everywhere, grouting is so rough, i would condemn that and not pay....( why should you have to pay for a mess like that!.)..rushed, poor workmanship imho......needs taking down and start from scratch with correct preparation and correct practice.....NOT GOOD!.....NOT GOOD AT ALL.......people doing shoddy work like this should be kicked out of this trade.....I see it all the time it’s shocking!......was it done by a Tiler or multitrader?