That sounds like a job for the pros if you want it to look good. If you can't match it exactly, maybe you can try a contrasting color, or something like that. For a temporary fix, maybe you can find some of that fabric tape and slide a tiny piece under the slit with the sticky side up. Then line up the slit, hold it closed, and push down on it to stick it on the tape. Just an idea, but it may be impossible to line it up and stick it straight. If it sticks in a bad spot, you may create a crooked mess. I think I would leave it to the pros for this one.
LOL< I don't blame you for not wanting them to touch your car anymore. I had a similar incident with a boat I owned. It was in for a repair and they ripped one of the seats. They had an upholsterer that they worked with, come in and take care of it. He sewed in a new section. It came out like new. I was satisfied after it was done. I was upset, but things happen, and more importantly, they owned up to it and fixed it. Maybe an automotive custom interior shop would be your best bet. They may be able to do a local repair on the damage that may look acceptable. If you want a perfect job, they will probably have to do the whole section over. Probably a high cost though. You mentioned that the Dealer made the hole. Did they admit to it? Are they taking care of the cost of the repair? If they are taking care of it, it makes it a little harder to demand where it gets fixed. If they take care of it, they will have the shop that works with them do the work, if they have one. Sorry that happened to you...that really stinks.
