About 6 months ago, I had a Tile company come in to put in a tile baseboard in my bathroom, clean my grout and recaulk the tub. The contractor talked me into regrouting the entire bathroom because he said it was quicker, easier, less expensive and would last longer. He had good ratings so I trusted him.

Well, there were so many issue with the work... wrong color grout, the grout itself is uneven, has dips and holes, they cut my tile with the multi-tool in over 20 places and took big chunks out of one of the floor tiles. I'm devastated.

The caulk was so uneven and ragged that it was impossible to keep from molding. Plus, the caulk running up corners, where the sides meet the back, covers about an inch of tile in some places. So, I decided to recaulk the tub myself because I've been unable to remove the mold from the dips and rough spots. I managed to get the silicon caulk off but there is another layer underneath. I'm not sure if it's grout or sanded caulk but whatever it is, I can't get it out. My tub is acrylic and I'm terrified that I will scratch or gouge it in the process. I know this wasn't there previously because we had replaced the caulk 2 years ago and we took all the old caulk off.

• How can I tell if that last layer is grout or sanded caulk?
• Can I apply a bead of silicon over the top without taking out that last layer until I can get a professional to do a proper repair?
• If so, what would you suggest to kill any mold that's already there before adding a new silicon layer?

back wall of tub with first layer of silicon removed

corner where back and side walls meet. I think this is silicon caulk.

Corner where walls and bathtub meet.