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

If it's your state refund that you're concerned about, you can track it here:  https://ttlc.intuit.com/community/refund-status/help/how-do-i-track-my-state-refund/00/25571