Client has submitted wrong VAT to Upwork

[56751e13]

Hello, I live and work from Germany. Now I had a client from the EU who gave an invalid VAT number on Upwork. How do I know this? I have to check the VAT officially for my accounting and for writing invoice. The check showed that the number he entered is not valid. Namely, the client is under the assumption that Upwork is his contractual partner. But this is not correct. I am. And in this case, since my client lives in the EU, he has to pay the VAT (reverse charge).
Now the client has said that he does not want to discuss with me any further.
Do you have experience with such a case? Because, if I don't get the valid VAT from him, I have to pay the VAT in Germany. Unfortunately I can't find any correct data about him on the internet. Can Upwork claim the number?

Kind regards
Stephie

[spectralua]

Upwork covering all info, them won't share it with you.

You can report that you think is fake info used. Thats all. 

[56751e13]

Thank you.