I bought images from Adobe Stock and was sued by another company. What should I do? I am in China.

 Can the author issue a certificate of originality on my behalf?

By @andyshicy

You can only be sued by the rights' holder. You go to your account (https://stock.adobe.com/Dashboard/LicenseHistory) check the asset, screen copy the licensing

...and send that proof to the one suing you.

If that is not enough, you need to contact Adobe. See here: https://community.adobe.com/t5/stock-discussions/fotolia-gt-adobe-migration-zugriff-auf-den-alten-lizenzverlauf-wegen-abmahnung/m-p/14718921#M77893

If you are getting sued, you need to react fast.

By buying and downloading an asset from Adobe Stock you are accepting Adobe's license agreement. That agreement, along with proof that you downloaded the asset from Adobe stock, is your proof that you have the rights to use the asset.

 How can I be provided with evidence that I can use this material? Can the author issue a certificate of originality on my behalf?

By @andyshicy

The author can't issue a certificate of originality. The best option if you are being sued is to talk to a lawyer!