2000 Volkswagen TDI car would not start

I drove my VW diesel TDI about 100 miles into a parking lot and shut it off. I returned from the 3 hour meeting and car would not start. Engine only turned over, and over but would not start. We connected jumper cables to another car battery and still would not start.

Had to have car towed to dealer, and code indicated that the engine was locked into immobility mode. Dealer replaced the main power relay and told me what they replaced was NOT a factory part. Replaced part # is PA66-GF30, listed as Kracker and Made in Germany.

I do not trust dealer, and they charged me > $200 to replace this $36 part.

Can someone explain what may have happened and why they said this was NOT a factory part, even though it indicates Made in Germany.
Thank you.