Problems traveling to the Dominican

Hi....My family and I have a trip planed in two weeks to a resort in the Dominican. I am a Pd patient. We chose to ship my supplies ourselves via FedEx due to Baxter only delivering to the airport. A few days ago the resort informed us that they now would not be able to accept my supplies any earlier than the day I arrive. We will not arrive at the resort until after 4pm. I'm going to try to pack at least a days worth just in case FedEx doesn't show that day. Would anyone have any advise or maybe had to ship their own supplies before. Is there something special to do to guarantee they arrive on time? Thanks in advance.