Southern Railway — too high parking charges at tambaram railway station

When I go to tambaram from egmore, i have parked my two wheeler in the egmore railway station at 7.40 pm and told them that I would come back next day and they told me to pay Rs.20 and I have paid the same. When I come back on second day at 6.40 am next day, they told me to pay another Rs. 25 apart from Rs.20 which i have already paid. when i enquired they told that this is the rate fixed by the Government. Totally I have paid Rs.45. That means for extra four hours I have paid 25. In the notice board it is mentioned as for 12 hours the charge is Rs.15, for 24 hours the charge is Rs.20, and after 24 hours the charge is Rs.25.What does it mean, is it fair rate. Even for two days parking, they would have charge Rs.40 only.But I have paid Rs.45 for one day and four hours. can Southern railway take necessary action against this.
The staff working in the parking stand they behave like rowdys when i enquired about this they told that you go and complaint at an