No — Split Pay can't send money back to your tenant on your behalf. Once a payment starts processing, it's done from our side.
If you and your tenant agree on a refund, you'll need to send the money back to them directly through any normal method — Zelle, bank transfer, check, whatever works.
If a payment is still scheduled and hasn't started processing yet, your tenant can cancel their autopay on their end. Ask them to do that if you want to stop an upcoming payment.