iPhone box opened and no SIM card in package

I’ve just received my new iPhone, delivered by DPD. The package appeared to be untampered with. However, on opening I found that the iPhone box was opened both ends, although the seals were intact, as if the top part had been ripped off. Plus dirty marks on the box. There is also no SIM card in the package, although my order should have included a physical sim.

I’ve raised a complaint via online chat, which took almost a hour. This will now take 7 days to investigate. Is this phone safe to even use? I’ve read advise on the internet that states if box is opened then it could have been replaced or tampered with. For now it appears that I will just have to leave the phone in the box until I hear back from iD mobile. Also, where is the SIM card? The operative simply told me to go into Curry’s a get a replacement SIM, but didn’t address question of who now has my SIM card?!