Purchase Iphone from Reseller in Greece(EU) and DOA Problem

Hello Community,

What is the official procedure when you buy an new Iphone and has a defect after unboxing? (Unable to find Physical SIM).If the Authorized Service diagnose that the phone has a factory fault what you will get a refund? a replacement unit(Packaging?) or a new device?.

I purchased an iphone 12 from a Greek supply chain in Greece after unboxing it was unable to detect the physical sim i try all the troubleshooting steps.The next day i went to the store delivered it and the take it and they take it to their service.I am unable to find out if the device was checked from the official authorized Service provider in Greece(Infoquest).Yersteday i was informed from the store via sms that the device will returned to the store for pick up i can see that the imei has changed and s/n has changed.The customer support doesn't know or asnwer if the device is a replacement unit or refurbished unit or new one and they tell me in the store that the i will get only the device despites that i delivered everything box cable papers in perfect condition.I held the device only hours.I am very dissapointed i spent a lot of money and the device was factory faulted.

Regards,

A newbie user