1. I am again informing you that charge leveled against sec.498A is not compoundable i.e. not withdrawable.
2. It was a mistake on your part to mention in the MCD petition that she will withdraw the 498A complaint with in September' 2016.
3. You can not filr a cheating case against er for not withdrawing the 498A complaint since it is not compoundable. if you file such case, then she will submit a letter addressed to the police withdrawing her said complaint. Please note that even if she writes to the police for withdrawing her said complaint, police will not be able to withdraw the case since it is not compoundable at all.
4. You shall have to take the risk of paying the fist installment of rs.2.5 lakhs.
5. You can ask her for submitting the affidavit as suggested in my earlier post affirming that the said complaint was out of rage and has compromised with you in family matters and does not possess any such grievance against you now.
6. File the quash petition before the date of the 2nd motion for your MCD as suggested in my earlier post wherein she should depose in support of her affidavit to enable you to get the FIR filed against you quashed.