My sister refused my order delivery... can I do something?

Call FedEx. They will hold your package at their facility and you can pick it up. However, when my iPad 2 was in transit, I received an email from FedEx and included a form that I could fill out and sign and leave for the delivery guy so that he could just leave the package without an in-person signature.. You should see whether that's an option for you (if you trust your sister, her husband and your neighbors).