they are goneim here on a non-resident visa since 2007. since that time i paid few thousands from my paychecks for medicare and social service. is there any chance that i could get my money back?
Actually, the only way to get any benefit from those contributions -- at retirement age -- is (a) to continue working and contributing to SS for 10 years, or (b) if you worked in a country that has a "totalization agreement" with the US, which would allow you to combine your work history in that other country with your US history to qualify for SS.
Otherwise, consider it as a tax.
Contributing for 10 years can i get the money if i am not in usa ?
If you are eligible for SS benefits, then you can collect.