Yeah, slaves are high value property. Once you are branded there is no "legal" way to be free. Not to my knowledge. You will have to escape and then pay for brand and chain removal and get a new passport.
Edit: I just discovered that since I renamed "Gold coin" to Gold Coin" (Among other things in the "DataItem.txt") it is now showing up as two different items in the bank deposit, as shown here:
View attachment 881380
So, withdraw the "old coins" close the dialouge open inventory:
View attachment 881382
Then deposit the gold coins again and you're good to go:
View attachment 881383
I am pretty sure the bank deposit and Lonas inventory are the only places this can happen since other storages resets when you leave a map.
BTW, I just went to the captain to check what the fare was now. "28 Gold Coins" So, I need to do some more quests... I wan't to bring Cocona as well, so make that 56 gold coins, minus what ever Cocona earns at the tavern.. : ) My world danger is at 82. Enemies are getting pretty tough now..