Red Exclamation mark on my watch "!"

I was updating my watch and it turned off. Now I can only see red exclamation mark on the screen.

I took my watch to a local authorized apple service center and they told me that I have to replace my watch for 350 euros since it is out of warranty already. And to my question, isn't there any solution for this to reinstall the system or something?, he answered: No, the only solution is a replacement.

Can someone prove this wrong, because I am pretty sure there is a way to repair it, and this service center just doesn't know how to do their job properly.