Construction Agreement Cancellation

I booked a flat at 2018 with a builder in Chennai, and did a construction agreement and paid 1% stamp duty and 1 % registration fee whcih was 98500 rs, under my name and my wife name, the project was ongoing. Later at 2020 me and my wife got divorced legally. I asked the builder to remove her name from the property during sale deed registration. The builder said first we need to cancel the old construction agreement and do a new one with your name alone, later we can proceed with sale deed. We both agreed but the builder said for cancellation also you need to pay 98500, and for the new const agreement separate 98500, so I paid 197000 rs, but during the cancellation time I got only an acknowledgement receipt from builder that they paid the Tamil Nadu govt only 98500 for new const agreement. When asked about the cancellation charges' receipt, they are saying will send soon buy yet to receive. I suspected them and checked online, it says only 100 rs for cancellation of documents, can you clarify.