Cancelling and re registartikn5of sale agreement

Dear Sir, I have purchased a plot in bangalore and got registered it in feb'20..after that I.made the payments (self fund 60%) and taking home loan for 40%..when the sale agreement is executed and the original documents were sent to my old address by the vendor appointed by builder. I was not.aware about the courier details and all and the lockdown started..when we enquired them about the sale agreement they told its been sent to my address, but upon enquiry and search we were unable to find it out..now vendor accepted the mistake and took a copy from sub registered office and shared with us..but now bank not ready to issue the loan because of unavailability of sale agreement...after internal discussion between builder and bank,they are proposing to cancel the sale agreement and execute new sale agreement on same day..so that bank will get the sale agreement ..also they saying same day sale deed will.also be executed..they said the charges related to sale agreement execution will be born by the builder.. But pls let me know is it safe to do this way..what are the things I need to be extra cautious