First of all, I want to assure you that we at CGTrader are invested in solving this issue together with you, our designer community. We have already contacted the website owners and asked them for immediate and full cooperation in removing your models from their listings. You can also do this via contacts they have on their website.
In the meantime, I would like to invite all the potentially infringed designers to fill a copyright claim to Google here: https://www.google.com/webmasters/tools/dmca-notice?pli=1& . As you, the designers, are the owners of Intellectual Property, your claims are more valid than ours.
I, Evaldas and other members of our team will keep you updated in this process. I would also like to encourage you to share the suggestions to your fellow designers on how to tackle this issue.
All the best,
Product Owner at CGTrader