I live abroad permanently, and received ss income for the first 9 months of 2009. I then stopped the payments, because I realized that my gross income in the country I live will exceede $16000.
What amount am I obliged to repay, if any, since I am not obligated to pay any federal income tax as my income is less then the allowable deductable for living abroad.

In which country do you live? It is likely that, if there is a tax treaty, the Social Security benefits are NOT taxable by the host country.