How to unlock an iPhone blocked by a phone provider company?

Evolprim wrote:

How can I unlock my phone after it has been restricted and blocked by the phones provider company?

If your phone is carrier-locked, only the carrier who holds the lock can remove the lock and allow you to use other carriers. Typically they will not do so unless you are a customer in good standing and any contract or subsidy that is associated with the phone is fully paid off.

How to unlock your iPhone for use with a different carrier - Apple Support

If your phone is blacklisted, to keep it from receiving cellular service, that may be because the phone was reported lost or stolen. A lost or stolen phone might be "bricked" by blacklisting, by Activation Lock, or both.

The All Too Common SAD Reality of Buying a Used iPad/iPhone – Apple Community

How can I unlock my phone after it has been restricted and blocked by the phones provider company

You yourself cannot do this....and....neither can Apple.

The carrier blocked the phone. Only the carrier can remove the block from the phone.

Your only chance is to contact Customer Support at the carrier to see.....IF.....they will unlock the phone for you.

and if you don't mean sim locked to a carrier but block because say the IMEI was reported stolen, then you can't it's the carrier which has blacklisted the device, the device have no power to alter the carriers block systems