Effective August 1, 2017, the U.S. Embassy no longer issues a Social Security credit certification letter. In accordance with Chilean Law 18.156, foreign workers who are hired by Chilean companies and have been paying into the Chilean Retirement System (AFP) through mandatory deductions in their salary may be eligible to retrieve this money if certain requirements are met. You should check with your AFP to see what those requirements are.
The U.S. and Chile entered into a Totalization Agreement in 2001 for the purpose of avoiding double taxation of income with respect to social security taxes. For more information on obtaining a Social Security Earnings statement, contact Social Security using the online form.