National Highways Authority Of India [NHAI] — Fas tag available but Take double charge in toll plaza

Address:

Junagadh ( Gujarat)

In my car fas tag already available and balance also 137/- rs.when I have done single entry in gadoi toll plaza 65/- rs debited from my account but when I have have returned from gadoi toll booth they have charged double amount when I have available balance 72/- rs and toll charge only 35/- rs return fee then how they will charge double when balance availble????