Can builder ask amount which is paid in cash & updated in agreeme

As per Sale Agreement Builder - "The FLAT/UNIT Purchaser has paid stamp duty of Rs 1,80,200.00 (Rupees One Lakh Eightty Thousand Two hundred Only) along with appropriate registration fees herewith. The Parties hereto shall be entitiled to get the aforesaid stamp duty adjusted leveable on the conveyance, which is to be executed by the Propmoters and the Ownership Party herein in favour of the FLAT/UNIT Purchaser herein. If additional stamp duty is required to be paid at the time of conveynance the same sahll be paid by the FLAT/UNIT Purchaser...." During Registration he has shown this clause and by reading it i have given him money in Cash for that i dont have any proof. Now when i moved to Consumer Courd for Deficiency in work builder is asking money or show the proof of payment. Can this will proove that Builder has already taken Money for Stamp Duty and Registration? When this clause is there then also builder can ask money? What if Builder file case against me? Please Reply your valuable feedback. Thanks in Advance for your kind support and suggestion which are helpful for me to proceed further.