Shoot me a private message with your account details (Customer ID/Mobile number) with your best contact number and preferred time. We will raise this with our Mobile Specialists for further investigation and handling.
How do I private message (PM) in the community
See what they are saying in Apple Support site:
"The switches that select networks are installed on your phone by your carrier, not by Apple. It’s part of the Carrier Settings file that is installed when you activate a phone on a mobile network. If there is no 3G switch it is because the CARRIER DID NOT INSTALL IT; Apple has no control over what the carrier installs on your phone.""
"Thus, IT IS NOT AN APPLE ISSUE! The iPhone 12 supports 2g, 3g, 4g and 5g. And if there is no 4g or 5g service available it will revert to 3g. You just can’t force it to because your network operator doesn’t want you using 3g. Most networks will be eliminating 3g completely in the next year or so. Even before the official shutdown carriers are switching many towers from 3g to 4g to improve 4g coverage. For every 3g channel on a tower there is one less 4g channel available for that location."'
... View more