No sparks...

I just don't know anymore and the workshop doesn't seem to know anymore.
I bought my dream v8 two weeks ago. Unfortunately, it's slowly becoming a nightmare for me.
I got the car from Austria and everything went great on the way home (800km), absolutely no problems. the next ta I was on my way in the evening with the car, coming from the cinema and the gasoline pump strikes, adac called and towed. after which I got the petrol pump (thanks to purerm hüring) the car ran again, but only once and since then nothing is happening anymore. the problem, as far as I've come, there's no spark left. However, the immobilizer has been blocked since 1997. I also used a new baterie because the old one was ready.

Is it in the range of the possible that the cause has to do with the immobilizer, or with the battery change?

I have now brought the car to the workshop (no vag, free), and they don't know any more...