On and after April 1, 1947, any permanent fireman who has withdrawn his accumulated contributions from the retirement fund while remaining in the status of a permanent fireman and not on account of retirement, withdrawal or dismissal from service as provided in N.H. Rev. Stat. § 102:21, shall thereby forfeit all right to future reinstatement to the benefits of this chapter. On and after said date no permanent fireman shall be entitled to withdraw his accumulated contributions to the fund while in service as a fireman. No benefit under this retirement system other than a return of contributions as provided in N.H. Rev. Stat. § 102:21 shall become payable to or on account of any member unless said member was in active service as an employee in the fire department at the time of becoming eligible for benefits hereunder.