After you file

I am a senior now, full time student with credits and my twin brother got the American opportunity credit, but I didn’t. The IRS didn’t send me a letter; i got cleared for the opportunity credit as it said ready to mail, but then vanished by the time I went back into the app after a weeks time. Every time I tried to amend the return, it said I qualified for the credit, but it wouldn’t add it to my federal return after I signed the files.