who has used Island Marketing Ltd. for their shore excursions on West Caribbean Cruises?

We are taking a cruise later on this year, the crusie line don’t offer the shore excursion I want . I want to go white river tubing and go to Dunns River Falls . The lady that’s in charge of the group we’re going with says not to use other company for shore excursions use only the crusie ship excursions but Island Marketing is cheaper and goes where I want to go. They also take smaller groups then crusie line does. The lady has sailed with this line sevral times in the past and says she gets special treatment because of all the people she gets to sail each trip. I’m thinking the only reason she wants us to use the crusie line excrusions is so she gets more discounts or better treatment.