Anti theft system activated

So here’s the deal. We travel with it a ton with the kids. The fall we needed a new engine which was expensive and sucked, but whatever. This past weekend I had the car in the city parked for a while, when I went to start it, it wouldn’t start. When I turned the key it didn’t click or turn over at all, but the lights and radio turned on. After some Googling we decided that it was the anti theft system causing the engine to not start and we read to try to unlock the door with the physical metal key. The next morning we went back, low and behold it worked! Phew, we just dropped $3,000.00 on a new engine and now we don’t have to take it back to the mechanic, great. I should mention, we do think someone tried to break in because there’s a mark on the window that looks like a slim jim was used.

So anyway we think everything is good, until Wednesday when it happens again and this time the key in the door trick doesn’t work. More googling, we try disconnecting the battery, no luck. Eventually after about two hour of trying, it works. And then tonight our nanny had the car and the kids and it happened once again, but this time no tricks are working. Have you heard of this? Do you know how to solve our immediate problem of getting the car to start or our long term problem of this not happening every 2 days?