Is this a resale of stock illustrations?

Question

Design

Good afternoon!
This is the situation: I created promotional vector illustrations for a company. (All rights to the illustrations belong to the company under the contract). Stock illustrations (elements, individual objects) were used to create illustrations.
I paid for stock.
On the company's website, I find out that the illustrations I made are for sale (!).
Q: Is it possible to resell stock illustration elements in this case? Is there a copyright infringement of the stock illustrator? Who is responsible for this (the fact that this will be an illustration for sale was not specified
in advance) Thank you in advance!

Answer 1

> Is there a copyright infringement of the stock illustrator?
Telepaths are still on vacation. How can we know what rights the "stock" has shared with you for a fee, and what not?

Answer 2

You have a composition there, i.e. some derivative material, not a banal resale. Accordingly, in the conditions on the stock, it should be stipulated that you can sell derivative materials, for example, with the mention of the authors of the original.