After you file

I haven't received a letter from the irs yet, but it's been over 21 days so I called them and they told me that my account is under review and they need until June 13th (I was accepted on Mar 20th) and they also told me I might be receiving something in the mail.... no reason as to why. After reading this thread I did request my transcripts, maybe that will give me some kind of answer.
This is super frustrating though