I factory reset my iPhone and now it's not supporting my sim card

Contact your carrier.

That would indicate your phone was hacked to illegally unlock it and has now reverted back to its original carrier locked state.

Only the carrier it is locked to can legally unlock it.

how do i get my simcard to work on my iphone 7

You get a sim card from your carrier.

Same problems brother

please tell me bro

The answer has not changed..