Can you post the txid here on the forum?
So I'm a little confused, and wondering whether the "available" balance amount shown in the wallet is a phantom vestige of many years ago, and not real... or whether there's some other way to salvage what appears to be a functioning wallet?
The only way to be sure is to check on a block explorer like
https://blockchair.com/Check the original address to know if there are any funds on it, also check the test address for any incoming or confirmed transactions. If the funds are not in any of these, then it could well be a
phantom vestige as you say, probably a canceled transaction (through a double spend) which was received some years back