Thank you very much for your feedback regarding your booking experience. We are very sorry to hear of your difficulty using our website. Viator’s system was designed with the utmost flexibility in mind for our customers, and we do strive to ensure the customer online experience is a smooth one. We see that you were attempting to make a group booking for a total of 16 passengers, which may have had something to do with the errors you received. There is no indication on our end that changes were attempted, however we do see that the supplier has confirmed your bookings. If you do need assistance with making changes, we ask that you please contact us via Facebook, Twitter, or our Live Chat option along with your booking reference number(s) so that we can assist you. We again apologize for the inconvenience and do hope that your upcoming trip in May is both a pleasant and memorable one. It is also our hope that this experience does not prevent you from booking with Viator again, as we would love to have the opportunity to be of excellent service to you in the future.