How could I proove that I own the copyrights for 3D Image

[Alexander ABiator]

Hello community!
My 3D works are often used without any permission and are pretty widespread. So I wanted to start selling them properly.
Recently get a refuse due to my work could violate some intellectual rights. Here is this 3D art on my DeviantArt gallery https://www.deviantart.com/renderdock/art/Silver-arrows-492114917 
It's an aircraft, not an iPhone or somewhoos property but a render of 3d model that I made in 2014. But it could be seen on other resources, violating my copyrights 

So how can I resolve that issue? 

[RALPH_L]

You can sign the release forms yourself.

[Alexander ABiator]

Thank you, Ralph. Will try it 🙂

[Nancy OShea]

I would guess that DeviantArt have a complaint procedure you must follow when you feel someone on DeviantArt violates your copyright.

Adobe Stock requires you to submit a signed Property release with original artwork.  This gives Adobe and anyone who purchases a license the right to use your image.  Photos and illustrations you submit to Stock must not violate another person's trademark, copyright or design patents. See link below.

https://helpx.adobe.com/stock/contributor/help/terminology-and-importance-of-copyright.html

[Alexander ABiator]

Thank you Nancy! 🙂 

[Abambo]

Be sure that your design is not too similar to existing designs. And of course, the keywords and the title must not refer to a corresponding design. MIG Jets would also be rejected by an American company.

[Alexander ABiator]

Thank you! Will try not to use such keywords