How to check status of case id for activation unlock?

How can I check status of a release activation lock by case id?

I submitted a request to release an activation lock for a device that I bought from a 3rd party.

And received a case ID (a long number) for that request.

I did not receive any confirmation via email or on my apple (iTunes) account that any case was submitted.

But I can't find anywhere how to check the status of that request.

It is not recognized as a customer service request.

Does anyone know where I can check the status of the request?

Thanks!