Our hands are tied. We'll leave it if it's safe and we have permission to. A lot of shippers require a signature. I don't want to come back tomorrow for the same delivery any more than you want to wait until then. You sound like the customer who says we left a note but didn't knock or ring the bell. Really???
It's not your fault. Its the clueless management. Fedex is the only that who does not know that tenants sign a document of agreement with the leasing office - which authorizes the leasing office to accept deliveries on their behalf. Shippers get their signature from the leasing office. Please send an email to your CEO and break the news to him.