I bought the phone and now I can’t insert another sim because it’s showing sim locked

Apple cannot unlock the phone. Only the carrier can unlock a SIM locked phone.

The phone that you bought was locked to another carrier. You will need to contact that carrier to get them to unlock the phone......IF.......they are willing to do this. They are probably under no obligation to do this.

Things would be tons easier if you could get the former owner of the phone to contact the carrier and ask them to unlock it. If they won't......ask for a refund from the seller. You don't want that phone.

ndifon146 wrote:

Please help unlock my iPhone

The carrier lock is just one of the concerns when buying a used device. As Bob Timmons said, only the carrier is capable of doing that and they may even refuse to unlock the phone. For more information on that and other concerns when purchasing a used phone, check out this Support Article:

The All Too Common SAD Reality of Buying … - Apple Community

I am sorry that you were scammed, but there is nothing that we can do to help.

Next time, make sure that you buy an unlocked phone. Do not ever buy a used phone online.