In August 2019 I bought bitcoin via a Germany based service (Bitwala/Nuri - now insolvent) back in the days. They were stored on a mobile wallet. The phone on which the wallet/app was run is now out of service (battery gone). During creation, I wrote down two seeds, one called “main key” and “backup key”, both consisting of 12 words and also something called a “reference key”
I now wanted to recover/gain access to my bitcoin again and imported the main key to my trezor model one (successfully) via the advanced recovery option. However, the Trezor suit falsely shows balance = 0
Can anyone suggest the best course of action? It was my understanding, that I would be able to recover the bitcoin using the two 12 word seeds.