There is a problem with my iphone

Actually, it sounds like you have a phone that has been blacklisted after being reported lost or stolen.

Where did you get the phone?

Each Apple device is linked/associated with an Apple ID of the person who did the setup.

Activation Lock prevents anyone who is not the owner from using this iPhone.

To unlock this Phone, you need the Apple ID and password that were used during set up.

You wil need to contact the previous owner to have them remove this device from their account.

If you were given this device or purchased it secondhand, you wil need to contact the previous  owner to have them remove this device from their account.

If you bought second-hand, send the iPhone return to the seller & ask your money back.

Buying a second-hand device is not without risk, unless you buy from an Apple Store or an Apple Authorized Reseller in your region or a reliable store.

Apple cannot help you.

You cannot use the iPhone.

What reseller?

When?

That's not an activation lock message. That's the kind of message you get when it's been blacklisted by a carrier or completely blocked in Apple's system because it was stolen from Apple Stock.

That is exactly what I would expect to see if you bought one of the devices that were stolen in one of the many smash and grab robberies that have been in the news recently.

See this Apple article: If you see No Service or Searching on your iPhone or iPad

https://support.apple.com/en-us/HT201415

Then contact your service provider, looks like you have a problem with you SIM card.

Apple doesn't blacklist phones.

Where did you get the phone?

What did your carrier say when you reported the problem to them?