Bengaluru Metro Rail Corporation [bmrcl] — Staff not recharged the card

I checked the card balance before recharging it was 76Rs then at Mahalakshmi layout metro station I gave 100Rs note for recharge at the counter.The staff at the counter recharged only for 50Rs and didn't give change.Since I was in hurry to catch train I didn't recheck the card balance.Later while checking out I found card balance was not appropriate. Travel fare was 26Rs and balance was 99Rs.If the staff had recharged for 100Rs then balance would have been 150Rs after journey. Staff neither gave 50Rs change nor recharged for complete 100Rs.
Kindly take strict action against those staff who loot the public money.