You could still finish telling the story. How old are your basic “tune up” items? (plugs, wires, filters…) Has your check engine light been on and, if so, the dealer would have pulled error codes, so what are they?
You can easily narrow down the problem so that you know what to troubleshoot. This problem can happen for many different kinds of reasons so you find out what kind.
First, this can happen because your engine is getting flooded when you shut it down. This will happen if fuel injectors or the fuel pressure regulator are leaking into the intake after shut down. A quick thing to do next time it won’t start is hold the throttle pedal to the floor while you turn the key. This is a flood clearing procedure and if it helps you can guess the problem is too much fuel on restart. Checking the fuel pressure regulator is easy - find it & pull off its vacuum line. If there is fuel in the vacuum line, replace the regulator. Checking the injectors is not so easy & you might use a shop for that (but you don’t need a dealer).
Second, it can happen because ignition components get “heat soaked” and you get no spark. Just pick up a spark tester at any auto parts store and the next time it won’t start use it to check for spark.
Third, it can happen from various fuel system problems that result in insufficient fuel supply (the opposite of #1). When you pick up a spark tester also get a can of starting fluid. The next time it won’t start, shoot some starting fluid into the intake and if that gets it to fire - even if just a little bit - then you are probably looking at an issue with the fuel pump or some related component.
If you report back with what you learn from all of this people can tell you more.
You should also realize that an intermittent problem like this is often very difficult to track down. You are very unlikely to find any dealership’s service dept spending any serious time or attention on the issue. This is when you want a good relationship with an independently owned, local shop.