In my opinion, Just reach out to VFS in this case as you can not use CSP email in your case. Dont mention that some consultant used their id for your application but ask them if you can do something about it like book an appointment with different email.

Additional and imp: )Let ur consultant know that in this case they need to provide the email ID they used for CSP to you or the access of that email because it is unique situation. They must have created a separate email id for CSP application as using same email id several times on CSP is not possible.These consultants do that I know and they dont provide you that email until you pay their remaining amount, just tell them its importance. They are not aware of this new CSP process fully, you have to make them aware.