Order supposedly lost in the mail then as another is sent the lost one arrive? What to do?

Ok lets say you order something, after a LONG time you suppose it get lost in the mail and you contact the company, they think the same thing then send you a second one. After a few days, the package that was supposedly lost come to your door but the other one is in its way. Will the company call you to send it back or will they overlook it as collateral or something like that and just dont mind?