Why did I get my refund sent to me as a paper check when I provided the correct information to have it direct deposited

[DanaB27]

If the IRS was unable to direct deposit your refund into your account (you might have to check with your bank why) they will mail a paper check instead.

[Cassispiritgirl]

I have checked with my bank and they said they have no record yet of this deposit attempt and that I would have to contact the irs...I am not sure what to do next bc I have been in contact with the irs and they told me to call my bank. Can I please find an answer to this question?Unless I can get it directly into my account I am going to be without any means to take care of my financial situation 

[MichelleLO]

Does the Where's My Refund site indicate your check was already mailed?  Once you have filed your return, you're not able to make any changes to the refund method.