I stored 0.3 BTC on a Ledger Nano S (SegWit address). Then Zclassic said they would fork BTC (non-Segwit addresses) and ZCL into BTCP, and I created a non-SegWit address on my Ledger and sent the money to this address. I can see that the transaction has been verified on Blockchain.info, but the balance is not visible in the account on my Ledger interface. I am able to sign a message and prove that I own the address, but neither the address nor the balance shows up on the main interface.
Is this a bug, or have I lost my funds?
Well, if you can sign a message from the adress you send the funds too, it means that you have access to the private keys of that adress, which makes it extremely unlikely that the funds are lost, and rather plausible that something might be wrong with the GUI etc.
Are you sure your wallet is synchronized correctly?
Try something like this:
The ledger wallet application queries an online ledger service to get your current balance.
Sometimes there are a few problems with the connection to the ledger server.
Did you already try to click on the reload button a few times (this seems to work better than ledgers auto update)?
You could also try to remove the app data (settings -> tools -> reset application data) to force your wallet to synchronise.
Or alternatively, if that doesn't work, try importing the seed (again) or in an alternative wallet to see if the balances shows up there.