Refunding a useless advance ticket with all trains cancelled

Hi all. As part of a multi-stage paper-ticket journey I booked as a return on the Trainline app, I was booked with an advance ticket on a train on Friday evening on the ECML when it, like every train available that evening (per the app’s empty search results page) was cancelled due to the storm.

As a result, I never bothered printing off the tickets. It happens that I managed to book an alternative ticket from Hull Trains yesterday, but the LNER ticket was not transferable to them or any other TOC with whom I could complete my journey (with the ECML still being shut down for engineering), and I have another ticket back on Monday. Thus, due to the cancellation, the tickets for my original return trip are now entirely surplus to my requirements, and if I had not bought new ones I would not have been able to travel at all for the weekend due to the closure of the ECML. I believe I should be entitled to all of the money I spent on that return journey back as a result. Financially, this unused ticket is a big issue for me, as I am not too well-off at the moment.

Here’s the problem - as the train was cancelled and my ticket was purchased through the Trainline app, Delay Repay is unavailable and LNER tells me I need to get a refund through Trainline. The app’s refund page seems not to grasp that I was unable to travel at all using my original tickets, and only offers me a tiny refund for the parts of my journey that were not booked on advance tickets, which is apparently still conditional on me mailing them my unused paper tickets that I do not have.

What can I do?