Car Parking Issue.

I have Purchased a Flat in Pune. Initially while finalizing the deal i told builder that I do not required a Parking for which he was charging Rs. 200000/- he Agreed initially and later at the time of registration he called me 2 days before and said that Parking is Compulsary and i have to purchase it. i said i dont need it to which he replied in that case i cannot go for registration. I was forced to say yes as i have already paid the booking amount stamp duty and registration charges. he asked me to send an email in writing that i will pay Rs 200000/- for parking after the agreement and before possession and he need the money in cash. Now i am asking him to provide me the letter that he has sold me a car parking for Rs 200000/- he is not ready to give me in writing and said that i can cancel my booking. i have already cleared the complete amount as per agreement. The Clause in the agreement says. The Purchaser is given the right of exclusive use of One Covered Car Parking and the purchaser also agrees that is for any reason it be held that allotment of the car park herein to the purchaser gets canceled then the purchaser shall not be entitled to ask for refund of any amount or compensation as price herein agreed is only for flat and allotment is made ex-Gracia for beneficial enjoyment of the same. The Purchaser further agrees that he will not challenge any allotment of any parking space made by the promoter to any other purchaser. Please suggest i don't want to pay him the Rs. 200000/- in cash and i also needs the parking space.