I am employed by the United States Postal Service. I interviewed for a promotion. Prior to accepting the promotion I negotiated a Salary increase of 10%. When the promotion was processed I only received 8%. The hiring manager confirmed via email that she had agreed tot he 10% raise. Do I have any claim of false promise by employer?
You need to identify whether the hiring manager had the authority or implied authority to promise you the raise. If he/she did, yes you should get the raise.
If the hiring manager has no say in raises or just said you are eligible for a 10% raise, then no.