PATS type E system

Yesterday my car decided to not start as I was leaving work. It was fine in the morning and when I went to lunch from work, and when returning from lunch. Once I tried to leave from work at 5:30 pm, the
car would not start. My first guess was battery, but no, the battery is fine, it wants to start but just won't go. The fuel pump is fine, I can hear it kicking in and there is gas in the car. I looked around online and noticed someone saying something about their keys not working for some reason or another. I got both keys and removed all the keyring stuff and tried just the key alone. Neither key would work. The dash anti-theft light after trying to start does the super fast blink for a while. All signs online say that the anti-theft system has been screwed up somehow, and the dealership needs to do some work on it. Is this an expensive fix? I had the car towed to the dealership but they won't look at it until Monday the soonest. I guess I would like to know how the heck this happens in the first place. No one ever tried to start my car with another key, I keep it locked all the time, my work is a secure place, you can't get in without a key code and there are no signs that anyone pried open my door with a slim jim and tried to start the car with some other key. Anyone have any experience with their PATS system going on the fritz? I'm just curious why this would happen at all...
Thanks, Megan

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