New key fob totally lost keys now engine won't recognize key

I would say the dealer needs to make a good key , they ought to for that kind of $$

I would try to totally find your old key.

The same thing happened to me with my BMW 2007 525 I it's sat there for about a month when we lost the keys went to the dealership and he told me to hold him in for 30 seconds and then turn it over turn the key and it was cracking if you program and I got nothing to Yellow sign key sign with a line through it they don't tell me that they can tell it to the shop for $120 and then they could tell me whether it's the key or the car that is what I'm Keys you can't check the back can't cut take the battery out change it