You made a few mistakes:
1 mole of iodine reacts with 2 mole of thiosulphate ions.
amount of thiosulphate reacted = 23/1000 x 0.02 = 4.6 x 10-4 moles
amount of iodine present at eqbm = 2.3 x 10-4 moles
amount of HI present at eqbm is not 2g. the iodine and hydrogen present at equilibrium comes from the dissociation of HI molecules.
rule of the thumb: always work with SI units, convert 500cm3 to 0.5dm3