I am new here. A couple of weeks ago, the soap dish fell off the wall. So I bought a new one. I had been noticing that grout had been occasionally flaking off. So, since I had to grout the new soap dish anyway, I decided to regrout the whole thing. When I started removing the grout, I discovered that there is caulk underneath. So I started scraping it out with a box cutter. Then tiles started falling off. I think this installation was done when the house was built in the 60s. They used some brown substance to adhere the tiles to the wall. I have done a couple of tiling projects before. About 20 tiles have come off. At this point I am not sure what to do. I haven't been able to remove much of the brown substance from either the wall or the back of the tiles. I am afraid that if I use thinset to put the tiles back, it would be raised and the grout lines are very tight. Am I going to be able to repair it or am I now stuck with ripping it all out and starting over? I've tried to attach photos.