After you file

I received a reduced refund. Status says I will receive a letter within 30 days requesting further information. I filed mid February and never received the letter. On the phone I just get the automated services. FWIW the amount reduced was the exact amount of my earned income credit. I rechecked to make sure I entered the information from form 1095-A correctly. Apparently one can't do anything without the letter and I can't reach anyone to resend the letter or just resolve the issue over the phone. Suggestions?