Why hasn't my check came in the mail yet . It was mail on march 27

Please identify the source of the check you are referencing. 

I just talked to the processing center in Pennsylvania and they said that for some reason my check was mailed back to them and has been canceled now no one is at the IRS answering the phones to help me get another check reissued or help me to get a direct deposit going so at this point I really don't know what I'm supposed to do for whatever reason my check was mailed back to the Pennsylvania office and they canceled it do you know what I'm supposed to do at this point

My state tax reached my address but for whatever reason my Federal Income refund check was mailed back to the Pennsylvania office

The only thing you can do is keep trying to reach the IRS, they are the only ones who will be able to reissue a check.