Why I didn’t receive my refund yet ?

Call them and see if you have a 40 to 60 day stall letter.

Have you tried tracking your refund on the Where's My Refund? site?  Although most refunds are processed within 21 days of acceptance, some returns require additional review which causes a delay in processing. Please see Why do some refunds take longer than others? for more information. 

If it has been over 21 days since your tax return has been accepted, please see What if my IRS refund is taking longer than 21 days?