My iPhone is not compatible with Angolan operators
My iPhone is only compatible with a United States operator I'm Angolan I use Africell and Unitel.
If you are telling us that your iPhone is carrier locked, only the carrier to whom it is locked can release the lock.
If you are telling us that your iPhone is unlocked, but does not support the cellular bands used by those specific carriers (and vice versa), it is time to look for different carriers or a different phone.
Is your iPhone unlocked? And was it originally intended for sale on your country or region?