If the return has been processing for more than 21 days then you can call the IRS …
Call the IRS: 1-800-829-1040 hours 7 AM - 7 PM local time Monday-Friday
When calling the IRS do NOT choose the first option re: "Refund", or it will send you to an automated phone line.
So after first choosing your language, then do NOT choose Option 1 (refund info). Choose option 2 for "personal income tax" instead.
Then press 1 for "form, tax history, or payment".
Then press 3 "for all other questions."
Then press 2 "for all other questions." It should then transfer you to an agent.
Or you can contact your local IRS office. See this IRS website for local IRS offices - http://www.irs.gov/uac/Contact-Your-Local-IRS-Office-1
If it's been more than 90 days since the return was accepted then you can ask for help from the Tax Payer Advocate office:
At the following IRS website, find the USA map and click on your state, and it will give you the number of your IRS Taxpayer Advocate.
http://www.irs.gov/uac/Contact-a-Local-Taxpayer-Advocate
If you are unsuccessful with the Taxpayer Advocate for your area, you can also try the special IRS phone number for the Taxpayer Advocate Service at 877-777-4778.
More info on the Taxpayer Advocate Service:
http://www.taxpayeradvocate.irs.gov/about/who-we-are
http://www.irs.gov/Advocate/Taxpayer-Advocate-Service-6
Also see this article for more info on how the Taxpayer Advocate Service works:
http://www.irs.gov/taxtopics/tc104.html