iPhone 12 US Cricket Locked: understanding Tether Policy 2279

If it’s locked to Cricket in the US, they are the only ones who can unlock it.

Here are their requirements: https://www.cricketwireless.com/legal-info/device-unlock-policy.html

If you are not a Cricket customer and the device is not currently active on their network and has been active on their network for at least 6 months, they will not unlock it.

Did you buy the phone from Cricket US or from a reseller? If the latter, the phone was not properly prepared for resale and is useless to you.

What is tether policy..

If you bought from Cricket US, you need to seek their help. "Tether" sounds like a carrier policy, not that of a phone manufacturer.