I would think the carpet layers should bear responsibility for breaking your tile, regardless of how they react to the situation. This is especially true if caused by an errant hammer. If that's not going to happen, you'll need to find some pieces of tile that match those you installed. Hopefully you have a few left over. Remove the molding they installed to fully expose the affected tiles. Using a hand held grout saw, available at your local hardware store, rake out as much of the grout surrounding the tiles as possible. Use a razor knife and/or scraper to assist, if necessary. Next, the tiles can be safely removed without causing damage to the surrounding tiles. Use a flat chisel or scraper to get underneath the tiles and pop them up. Whatever thinset or mastic is left behind will have to be removed with your scraper to expose a clean substrate to adhere the new tiles to. Place the new tiles in position with the appropriate cement, and after they are set for 24 hours, can be grouted to match the surrounding tiles. This can be a tedious job, but care should be taken to avoid damage to the surrounding tiles.