Now, there may be other contract terms that are not obvious. One such term may be that the author not publish the work himself. The worst that could happen here is breach of contract. Since the only up-front consideration was from the author, this just means that Elsevier doesn't need to do what the author paid them to do, while still keeping the consideration of cash plus copyright license. It's sole remedy is to not coordinate peer review and not publish. Since it ALSO charges fees on that end, it has no reason to do that.
There must be a quid pro quo in a lawful contract. You can't bind someone to its terms unless you give them some valuable thing in return. Elsevier gives NOTHING to the author except the promise of publication and distribution. You can never prevent the author from making his own copies, ever. Your sole remedy is to write a penalty for doing so into the contract, but then you would have to PAY the author something to enforce it.
Elsevier does not give the authors anything, therefore they cannot demand performance under the contract. The only thing they can do is use one of those restrictive terms to weasel out of their own obligations under the contract while still keeping what the author gave them. They are absolutely in the wrong by demanding people take down their own work.
(I am not a lawyer.)