(a) Except as provided by Subsection (c), deposits representing interest or membership fees that are required of a member to establish service credit under Section 813.202, 813.302, 813.402, or 813.502 are not refundable.
(b) Deposits representing accumulated contributions are refundable to the member on application for a refund made as provided by Section 812.102.
(c) At the time a service retirement, disability retirement, or death benefit annuity becomes payable, the retirement system shall refund any contributions, interest, or membership fees used to establish service credit that is not used in computing the amount of the annuity.