A custom ROM was installed, and after an update, it is not detecting the SIM network. I spoke to a shop, and they said it is a software issue that will cost 1500-2000 BDT at Motaleb Plaza. Everything is original, and nothing has been changed. You can check it however you like. Everything works except for the SIM, and you can unlock it at your own responsibility. Only the phone and security documents can be provided, and you will have to come to the location.