[mothered]

was planning to buy 2 things and use the 'missing item' method but apparently they have CCTV footage of them packaging

First and foremost, how much does the Item weigh? When using the "missing Item" method, the weight Is of the utmost Importance.

CCTV Is of no relevance when you formulate your method effectively. If It's light enough, the package was tampered with during transit, hence you didn't receive the Item.