Never had a bad experience with Fedex. OOPS, on the other hand... I could tell you stories...
I used to live in an apartment complex. The UPS driver used to leave packages for us all the time... until one day, they started requiring a signature. When I called UPS to redirect the package to my office, they explained to me that a package is UPS's responsibility until it's in the recipient's hands, and they had a policy (which the driver evidently had been ignoring) that all packages delivered to apartments required signatures because they were more likely to be stolen out of the corridor. (Like you can't walk up to someone's house and grab a box.

)
If the same holds true for Fedex, and your package has "disappeared", you should be able to get them to pay for a replacement.
Good luck!