Dear Catherine,
Thanks a lot for your review. It means a lot to our small family business.
Usually we would also cancel the tour if not enough people, but to keep our guests happy we do it anyway even if one person books.
On the tour description its mentioned clearly that the transportation is only to Postojna cave and if you wish to visit other places there will be extra cost.
Usually extra cost is 25€ to visit predjama castle but since you bought the tickets of castle and cave together by mistake, our driver offered to do predjama castle visit for you @10€ total (not each way)
We wish to see you again for more of slovenia :)
Best regards,
daytripsfromljubljana.com