From an email
to a next step.
A person-to-person payment product could let someone send an email notification with the reason for a request and a route to review it. MyPayback could name that familiar moment of asking for money back.
A focused first offer might organise requests and route the recipient to a supported payment provider. The email would carry the notification; any transfer would use the provider’s actual payment process.
Possible starting point: payment-request coordination