Quality Grouting

So up to about the three month mark the grouting has been, how do I put this, well not the best. The tiling done by the first contracter had to be completely removed from the wall and started again, However the second contracter did not complete the tiling let alone the grouting so we have now got a third contractor to do this work four months from when we started. Just prior to me sacking the contractor they sent an apprentice to us for a day (no other tradesmen just the apprentice) and he did actually do some great grouting but the rest was a mess (I always thought that a qualified tradesman had to be on site with an apprentice)