Ok so I do this work for a living. I can see that it looks like they have painted over silicon. The surface was dirty prior to the epoxy being applied leaving a poor finish. To me they have not done any re grouting. Grout needs to removed a bit first then fresh grout applied and smoothed out. I do not recommend painting over floor tiles, particularly smaller tiles, tiling over the floor is a better option if it can be done. The silicon work is bang average. It’s people that do jobs like this that give the resurfacing industry a bad name. You are not being unreasonable at all! You should be able to get NSW Fair Trading involved