Question Details:I also checked with their civilian personnel office before my start date to confirm the amount was correct. They verified it was and sent me the confirmation in an email. On my start day, the amount was also noted on my employee file.
It depends on the wording of the final employment letter and what you signed with the government. You may have a valid claim to an increase in pay and back pay at the rate that you were shown in the letter.
I would recommend that you contact the law office of Steven Brown. He specializes in representing Federal employees.
His website is: http://www.federal-law.com/