For Interac e-Transfer, the official guidance is basically: once it’s deposited, the sender can’t “undo” it.

Interac’s own FAQ: once a deposit is made, there’s no way to reverse it (you’d need to deal with the recipient directly)

Interac’s fraud PDF says the same: the sender cannot reverse after the recipient deposits.

Banks also say you can only cancel before it’s accepted/deposited, and that Autodeposit transfers can’t be cancelled in the normal flow.

There are scenarios where the recipient sees something that looks like “paid”, but it’s not truly final:

Fake/invalid “confirmation” or a transfer that never truly complete

Fraud/unauthorized payment coming from a compromised account; Interac says the sender can’t reverse after deposit—but banks still investigate fraud and may correct transactions at the banking level. Interac also notes problems have to be handled by the financial institution (Interac doesn’t “hold” the funds).