Did you nano generate the same addresses (resp. the same
first address) after resetting it with the 24 word seed phrase?
If yes, then its probably just a display error or a network issue with their online service.
If, somehow, the address generated by your nano s after resetting is not one of your addresses and is unused then the seed most certainly doesn't match your old seed.
You could look into 'Settings' -> 'Tools' -> 'Sign message' and check the 'Address'-drop down menu and watch out for one of your addresses.
If it's contained, then everything is fine and its probably a display/network issue.
But if you don't find your addresses and it seems like a 'fresh wallet', you can still import your 24 word seed into another BIP39 compatible wallet (e.g. electrum[1]).
Make sure to choose the right derivation path:
m/44'/0'/0'/ when restoring your seed in a wallet different than ledgers native one.
[1]
https://electrum.org/#home