Mutual consent divorce petition is filed and final alimony payment is decided by both parties

Hi, I am facing mutual consent divorce and presented appeal to court as submission. Also outside court we have settled the alimony amount, however other party want alimony payment upfront but we want to give alimony amount after decree of divorce because mutual trust is not there. In all the document we had agreed on terms and conditions of it, in those document girl and his father signed it and biometric sign is also available. Now girl is sending an notice from her lawyer that they now want 50 lakh as alimony/expenses borne in marriage as extra and as mutual consent we have already given them cheque of 25 lakh as blank which will be applicable only when we get divorce decree. We have written letter pad , notary of mutual divorce and divorce petition copy which is presented to court signed by both parties. How to proceed further , since as a boy I fall prey to my wife. As her family is greedy in nature they are using law support for girl against us. We have following proofs, 1. Video recording that they have came to our house taken the letter , cheque , all gold jewellery and some cash by her father and their uncles. 2. Notary signed document by both parties that they will claim any alimony later and stated that it’s settled. 3. Divorce petition is also filed before court by both parties duly signed. 4. Official cheque of alimony amount of 25 lakh with letter of consent about its terms and conditions. This amount is decided outside court by both parties mutually agreed. Now spouse sent an letter by her lawyer, that they want life time maintaining amount as 50 lakh. How can we suppress such aligation made by my spouse. Open for suggestions, can they abuse Hindu law to get such alimony based on allegations.