I understand that you're unable to sign in to iCloud, and I'm happy to help. From what you're describing, these instructions should be appropriate:
As long as you still have your Recovery Key and remember your Apple ID password, you can sign in and add a new trusted device or phone number to your account. You can also remove any devices you may have lost, sold, or given away.
- Go to your Apple ID account page and enter your Apple ID and password.
- On the Verify Your Identity screen, select "Can’t access your trusted devices?"
- In the pop-up window, enter your Recovery Key.
- Go to the Security section and click Edit.
Remove the device you no longer wish to use to verify your identity. If you have additional devices with Find My iPhone enabled, you can verify them as trusted devices. You can also add additional trusted phone numbers.
If you can‘t sign in with two-step verification using your Apple ID