Ariel Gonzalez

Hello, I have a coming cruise on May in the Wonder beginning in Barcelona. I’m a little lost, I book some excursions in the trip planner. When I need to pay the cart? At this time or when we are in the ship? I have an other question, if I took the Voom surf, can I use the what’sapp for making calls or making call using the wifi. many thanks in advance. Ariel