M.C.G.M Pay and Park
Overcharging- wrong no of hours

I had parked my car in the MCGM parking near Shoppers Stop Ghatkopar from 1.30 PM to 3.00 PM. The parking charges as per the slip should be 13 Rs (upto 1 hour - Rs 10 Rs 3 for every additional hour). My driver was charged Rs 40 for this parking which is almost 4 times of the authorised amount. I have the slip from MCGM which mentions 40 Rs for this. Please guide.