Zelle never states that a payment can be reversed under no circumstances. The cited User Service Agreement (paragraph 11) basically relieves Zelle and Bank of any liability from the payment. In other words, they don't have the responsibility to reverse payments in a fraud situation.

Zelle Customer Service Number
Zelle is a United States-based digital payments network owned by Early Warning Services, a private financial services company owned by the banks Bank of America, BB&T, Capital One, JPMorgan Chase, PNC Bank, US Bank, Citibank and Wells Fargo.
https://reachcustomerservice-help.8b.io/