USCIS is checking to see if the Employer's business is active by asking these documents. Your employer should send the following:
1. Federal Tax Returns for the years requested (If they are new and do not have any let me know)
2. Telephone Bills, Location Google, Yellow Pages, FIRE DEPARTMENT PERMIT OR OCCUPANCY CERTIFICATE, Bank Statements and any other documentation showing their business existence. They MUST send any and all information available.
These type of RFEs are pretty common and If the RFE is responded with proper documentation, there should not be any problem in getting an approval. Let me know if I can be of any further help!