I read the following information in a letter to the Los Angeles TImes newspaper. A driver from Croatia into Slovenia stopped to have passports checked and noticed a station for buying toll stickers. They were not told at the border that they had to buy a ticket. Upon returning to Croatia, their passport were taken at the border and they had to pay a fine of 150 euros to get their passport back. Please help. Thanks!
I didn't find the right solution from the Internet.