Your best and only bet is to call FedEx and set up a day and time to receive the package or ask a neighbor or the superintendent of the building to sign for it.

You have so many days to claim the package from FedEx or they will ship the package back to the seller and the seller has two options, refund your purchase price minus the shipping charge or keep the package until you pay for the new shipping charges to get the package back to you, it all depends on the sellers terms and conditions.