How to protect myself from bank reverse

[#1]

Hello,

Recently, I made a job for a client, he took his file and thanked me and eveything seemed fine, but after over a month, I get a message that he reversed his transaction and that I need to pay the mount back or get my account locked.

so I wonder, why wouldn't upwork lock his account and ask him for the money instead? and what does the payment verification mean if money gets drawn back after over a month?

moreover, how do I guarantee and protect my work, when even clients that look legit and have a verified payment method will still take back their money after getting their work done?

[#2]

You can't.