[mothered]

I shipped it out now ill wait till they recieved it and when they say the box is empty I tell them that the package must have been stolen?

No, do not Initially say anything about the Item being stolen.

If they dispute It, tell them you've definitely sent It, and then ask them to email you photos of the package condition - just to check and make sure It was Intact during transit. That's when you'd bring up the signs of tampering and that the Item may've been stolen.