[Filippo000]

So when I get it, I say I've only received the t-shirts

Packages are weighed on consignment, so If the Items you're SEing with the "Missing Item/partial method" register a weight during transit and they cross-check with the carrier, your SE will fail.

What's the weight of the Items?

Are parcels weighed in Italy? When does this occur before shipment or at the time of delivery?

Suit composed of sweatshirt and trousers: from 1 kg to 1.2 kg
Shoes with box: 1.2 kg
T-shirts: 250 g each