DMRC — Customer care metro deduct extra amount

As I have taken entry from chhattarpur and taken exit at kashmiri gate with open exit gate by my card, today I have try to entry at same kashmiri gate metro gate was not open, while I contact to the customer care they deduction 50 rupess as a penalty from my card even this is not my mistake.
They took penalty from me why also amount should be only rs 36 Entry from chhattarpur to kashmiri gate they took Rs 50