We had a new bathroom put in in August 2012, it took around eight weeks to strip the room and remake it from scratch, and it cost tens of thousands for parts and labour. Overall the company (who I won't name for now as they're generally good and responsive, just very slow) has done a good job, but there's a problem with the grout between the tiles in the shower - see the pictures below. It's under warranty. They suggested this happened because we scrubbed the grout with a scrubbing brush - I'm not sure how my wife cleans them, but we were never given cleaning instructions. The rest of the grout in the non-shower parts of the bathroom are fine.

I notified the firm of the problem July 15 this year, and they came to have a look. We arranged to have it (and two other minor things) fixed while we were overseas on holiday in September, as it needed a couple of days to dry before repairs, and a couple of days to dry before use. Being without a single bathroom would be quite inconvenient. So while we were away they didn't fix the problem, despite two months notice, as the firm said their contract tiler had let them down. Instead they put a waterproof coating over the shower, which I'm not sure was helpful, as there's a thick orange waterproof coating under the tiles. The did one of the other fixed, and half did the third. They have said they will fix it, but haven't committed to a date, and haven't replied to my most recent email.

So my questions are:
1) What could cause this?
2) How could it be fixed?
3) Given they've had 2.5 months to fix this, and failed to fix it at the most convenient pre-arranged and mutually agreed time, can I have another vendor fix it and then bill the first company? Obviously I want to avoid doing this if possible, but I'd like to know my rights.




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