Indian Railway Catering & Tourism Corporation [IRCTC] — much less amount refunded for fully waitlisted(auto cancelled)ticket

Address:

713143

I booked ticket online for two adults(named Munmun Dey Mallick+1) train 12345(saraighat exp) on 22.11.2017 for DOJ 22.12.2017 from BWN to NJP, bearing PNR:[protected] of amount Rs.600/-, but the both tickets finally became fully waitlisted and hence became cancelled automatically.I was supposed to get a refund of almost full i.e.Rs.600/- (except the bank charges ), but I got a refund of Rs 480/-only . I boomed my tickets ditectly from sbi internet banking and Bank will not definately charge Rs.120/- as si called bank charges for refunding . Hence it is IRCTC who have refunded less money .Please refund the deficient amount without delay, otherwise give me vividand satisfactory explanation .