Post Office Delivered Envelop to Wrong Person?

I sent an envelope with a cashier's check to a friend in Newport Beach. I sent it addressed to her work place name and address, with attn: her name. I received the signature card back with an unusual signature (no one at her work place has this name), and when I tracked the envelope it said the sent envelope was received and signed at 6:45am, but my friend's business does not open until 7:45. No one received any envelope at her place of business when she checked. My question is how can an envelope be signed when the place of business that it was addressed to was not open at the time of the signature? There have been complaints with this post office (Newport Beach Ca.) with packages not being delivered, so we suspect an inside theft wiith the postal service. Please respond.