Kaplan case: N-400 returned

[AleksK]

Need some guidance on what to do next:

I helped my disabled friend to file N-400 application. He is eligible for filing under Kaplan stipulation (his SSI benefits were stopped for 1.5 years and restored only recently.)

We sent his paperwork to USCIS in May. The papers that were filed:
1. N-400 application, filled out and signed.
2. Fee waiver request, signed, with all supporting paperwork
3. Copy of both sides of green card
4. 2 photos
5. Blue letter from USCIS/SSI about Kaplan eligibility.

For almost three months, his paperwork could not be located, even if we knew for sure that it was received by USCIS (got delivery confirmation). Recently, he went to see local USCIS officer ,and took an exact copy of the packet that was filed to the appointment with him. The officer confirmed that everything was filed correctly, and promised to help to locate the initial application. Last Friday, the officer called and told him that the application is in a system. However, on Monday, my friend got the whole set of documents back by mail. The enclosed paper from USCIS said that application was returned because (cited):

1. No check enclosed
2. Need copy of both sides of Green Card.

Both reasons are complete bogus, because:
1) he is eligible for fee waiver and clearly requested so, and
2) the copy of both sides of green card is enclosed.

So, we need an advice on what to do in this case. He can be taken off his SSI any moment now.
Thanks in advance.

They have to approve a fee waiver but call them to ask and confirm the entire package, or even better, have an immigration lawyer intervene and review each part of his paperwork with the officials. They unfortunately will take it more seriously if legal counsel is involved.

[AleksK]

Thank you very much for your reply.
So, do you think that immigration lawyer (or rather public immigration advocate) may have a direct contact with USCIS and be able to follow through?
Do you know, by any chance, if USCIS field office can assist in expediting the case in extraordinary circumstances?