Key fob broke can’t start car?

There is usually a way you can unlock the driver door to disable the alarm

The starter should still work. the immobilizer just shuts off the fuel injectors when the key is not recognized. The battery in the key may not be making contact or the electrical portion of the key is messed up. I'd take your title to the dealer and have them cut another transponder key. You probably will need to tow your car to the dealer to have them program the new key to your car. This is another example of why you should always have 2 keys.

just get a new key for it, you did break the key right ? that should of given you a clue as to the problem, take the key to the dealer and get a cpl spares since you likely will use them.....

The key may be "chipped" and the chip fell off the key. Getting a key that is chipped to match the security code is not easy and it takes either a lock smith or dealership to do the job. Another term for this is that the key had a transponder in it and when it broke you failed to get the transponder part put back into the key.

I don't  know if this will work for your car. Security systems can be different and some times take a already matched transponder to program a new one:

https://itstillruns.com/program-chip-key-6527381.h...

There is usually a way you can unlock the driver door to disable the alarm

on my Nissan it was lock twice (left)  unlock once (right) or perhaps it was just the opposite  ;)

you can probably find it online