If the refund amount is a different amount then what you were expecting you will need to contact the IRS regarding this matter to see what changed or why they have a different amount.  You can pull up their website to find a local number or a toll free number so that you can call them.  You will most likely get a faster response from them with calling them versus going on their website.  An IRS agent will be able to pull up your file and answer any questions you may have concerning the amount of your return.

http://www.irs.gov/uac/Contact-Your-Local-IRS-Office-1

or if you want to contact a Taxpayer Advocate in your area.  See this IRS website for Taxpayer Advocates in your area and a toll free number.

http://www.irs.gov/Advocate/Local-Taxpayer-Advocate