The right to a retirement benefit, return of contributions, any optional benefit, or any other right accrued or accruing to any person under this chapter shall be exempt from any state, county, or municipal tax, except as provided in Code Section 48-7-27; exempt from levy and sale, garnishment, attachment, or any other process whatsoever; and unassignable, except as otherwise specifically provided for in this chapter.
OCGA § 47-4-120