How can i have a proof that i have paid the security deposit

I am going to shift in one single room oin 3 BHK. Two people is already living in two separate room in 3BHK. I m going to give security deposit. The who already living have agreement with owner. So I would not directly have agreement with flat-owner. I will deposit security money to tenet not owner. It might be in future they will deny that I had not pay any security deposit. what steps need to follow for proof that I have paid for security deposit ? Is the email from amount receiver will work as proof OR do I have to follow other procedure for future proof.