This may be a complete shot in the dark as to how doable this is… but I think there is already an app on the app store that pulls your TFL journey history including tap in, tap out / journey time? The app then alerts you if your journey was over the expected journey time and you can instantly complete a delay repayment form there and then.
Could this somehow be integrated for TFL journeys with Mondo?
I’m not sure about the specifics, but this sounds like tfl need to use the mondo API to build something. But it’s unlikely to happen
Oyster Balance & Refund by Cloudli Limited
https://appsto.re/gb/NZL1H.i
This is the app that has similar functionality. I think it would take integration the other way round? I assume TFL makes a lot of their live travel information public (for the like of city mapper?) and allows apps to integrate with journey history? Would probably be a big job for the benefit of a small feature however…
Even if it was kept simple with a notification a day later once the journey has registered and charged directing to a TFL web form to claim the refund?
Just an idea.
This does sound like a perfect candidate for a 3rd party integration via. the API. Though, I’m not sure there’s much to integrate on the Mondo side except maybe making a prompt appear in the feed/on the transaction as all the data would come from TfL.
I wonder if TfL could provide journey data within the Tx. I know airlines provide this type of data sometimes. It would he great if Monzo could
harness this data and make it appear in app.
You don’t need the transaction data, this service used to be able to claim refunds automatically until a recent update by TfL broke it. It doesn’t look like they’ve been able to put in the time to get it back up and running again 
This was about enhancing app experience than refunds