Key Issues - Car immobilized

Team, remote buttons were completely worn out of my MJD 2010 Linea. So ordered the Shell on amazon and transferred the motherboard. However afterwards, my car does not start. Remote buttons are working fine though. When contacted the service center, I have been told there should be a tiny chip inside the key, which I did not find (I was careful though that I should not misplace anything contained in my old key). Service center tells me I shall need a new key to be made for 4300/-. The challenge I am facing that I have to carry both spare key and the Remote Cell and no spare key at home in case of any eventuality. Suggestions most welcome to resolve this.

 

The cost seems to be fair from FASS.
I had ordered an extra key with flip keyfob and got it paired at FASS in 2013. The cost was 3999/- then (for the fob).
Outside guys would do this for about 5000/- (As heard from a guy in Bangalore in 2019/20).

On the fob not working after changing to new shell, I would suggest you to check with a professional key duplicator.
If you have carefully moved all items to the new shell, It could be some loose connection.
Or I may guess it would need re-pairing due to some lose contact - This should be detected at FASS. But since they are asking to get a new one, it probably may not be a cause.
The pairing cost alone would be about 400-500/-