IMEI unlock

Exactly, I bought the smartphone in South America, but not through any carrier. The phone was purchased brand-new, sealed in the box. Indeed, Apple's customer service confirmed that there are no issues with it. I've been using the phone for almost a year, and the local carrier I signed up with said they can't unlock the IMEI since they weren't the ones who initiated the block. I can use Wi-Fi, connect to iCloud without any problems, and set up the SIM card without errors, but I can't access the network. Every service I've spoken to agrees: it seems a mistake has been made. I'll try your suggestion. Thank you for the quick response.