How do I repair IMEI

The IMEI is the phone's ID whether there's one or two sim slots. Each slot has an IMEI number regardless of sim card inserted or not. I just moved my sim card from non 5G phone to a 5G phone. Both phones have two sim slots, four different IMEI numbers in total. My old phone still shows its two IMEI numbers without a sim card.

Either your phone was damaged or meddled with. Best suggestion is to bring it to a phone store of your brand and have them diagnose the missing IMEI number.