Mp Housing Board — Clarification towards the excess payment for purchase of plot

Address:	Gwalior, Madhya Pradesh, 474002
Website:	www.mphousing.in

I purchase a plot from MP Housing board, Gwalior recently.
MP housing board is charging service tax (15% of plot cost) and maintenance charges (10% of plot cost). I think they are charging illegally.
please take a necessary action and suggest me it is illegal or not.
I attached allotment letter of MP housing board in which they demand excess
money.