i buy a box pack 15promax 10 days ago but i am facing sim locked issu kindly help me to resolved this issu

Carrier Lock:- Request your iPhone’s original Carrier to unlock your iPhone and if they agree and do it, then you may know the further process here --> How to unlock your iPhone for use with a different carrier ...

Device Unlocking Policies | Verizon Privacy Policy

Unlock a Phone or Device - AT&T Device Unlock Portal

Unlocking your Sprint device - T-Mobile

FAQs about unlocking your Sprint device

Unlock Your Phone for Spectrum Mobile

That's not correct, sorry. To my knowledge, Apple cannot get involved in a "SIM locked" device, as stated in the link that I provided in my previous reply.

If you want to investigate more deeply, please contact Apple Support directly:--> Contact Apple for support and service

Regards and best of luck.

Giulio

See what happens in such a situation:--> How to unlock your iPhone for use with a different carrier - Apple Support

My suggestion: take it back to the seller and ask for a full refund.