I have been in the States since May 2004 under J-1 and worked for 6 months
then I entered graduated school and changed to F-1.
I filed my taxes using 1040 NR EZ, for 2005, 2006, and 2007.
I am working now with an EAD card.
The IRS told me that I did not received the rebate check because I filed the 1040 NR.
I realized then that for the IRS and for taxes puposes I am a resident, because I have been living in this country for more than 300 days approx. This means that I should have filed 2005, 2006, and 2007 as resident using 1040 EZ instead of 1040 NR EZ.
Is this true? Could I use 1040 X and do this amendment now? Will I be elegible for the rebate next year? Are there any deadlines for doing this amendments?

thank you

On F1/OPT, you are exempt from residency for 5 years. You must file non-resident tax return.

Agreed!

Unless you were married to a U.S. citizen or a resident alien during the times cited, you ARE a non-resident alien and must file the Form 1040NR or 1040NR-EZ.