How many ALJ's have you had? Have you looked up their approval statistics?

Getting additional documentation from specialists or having more tests done might be something to consider. Even if you get a new ALJ, having new proof would be highly recommended.

You should receive written notice of the remand. To catch this with a phone call beforehand isn't surprising.

Call your local SS office 30 days prior to your ALJ hearing and make an appointment (it will likely be at the hearing location) to review your file. They will let you take copies if you wish (bring someone if you're physically unable). You can submit missing and/or new evidence up to the day of the hearing.

What did the last Voc Counselor claim as far as your ability to perform prior work or any work?

Why did you not see the SS doc in person?

Do you have an active or settled WC or LTD claim? In my experience, an ALJ can confuse reports written by the insurance company's hired guns to deny benefits--which is an uphill battle and very frustrating. It is possible to overcome such "evidence" though.