Dear Linda,
thank you for your review, it is nice to hear that you have enjoyed with Gray Line on the tour and ofcourse with our lovely guide Ivanka.
Not sure where the problem arose, entrance tickets for the Plitvice lakes are 40€ per person which you were charged and you can check online the price of National Park entrance ticket. It is not Gray Lines fault that entrance ticket for the National Park is that expensive.
Regards,