Getting a Zelle charg-back isn't impossible, but it's not guaranteed. I wouldn't call it "safe" for the buyer, as they do not offer buyer protection. To anyone who is thinking about dealing with this guy: Be very careful. The fact that he's misrepresenting how Zelle works is a red-flag.
You can only cancel a payment if the recipient hasn’t yet enrolled with Zelle. You can go to your activity page within the Zelle experience, either within your mobile banking app or the Zelle app, choose the payment you want to cancel, and then select “Cancel This Payment.” If your recipient has already enrolled with Zelle, the money is sent directly to your recipient’s bank account and cannot be canceled.
Zelle is a great way to send money to friends, family or others you trust such as your personal trainer, babysitter, or a neighbor. If you don’t know the person, or aren’t sure you will get what you paid for (for example, items bought from an on-line bidding or sales site), we recommend you do not use Zelle for these types of transactions, which are potentially high risk. Zelle does not offer a protection program for any authorized payments made with Zelle - for example, if you make a purchase using Zelle, but you do not receive the item or the item is not as described or as you expected.