My number on my iPhone is disconnected

Have you contact your carrier?

Check if that phone number belong to you.

Then sign in to your Apple ID account page and edit / update your Apple ID details -> https://appleid.apple.com

• edit / update your trusted phone number.

Check also:

1.

Remove and reinsert the SIM card.

If it doesn't help visit your carrier, maybe the SIM card is damaged, ask for a replaced (new) card. Normally it is free.

Ask also to check if the SIM tray is bent, as even a tiny misalignment can cause the SIM card to not fully connect with the internal contacts in your iPhone.

2.

See these Apple articles below:

If you see No Service, Searching, or SOS on your iPhone or iPad

If you see No Service, Searching, or SOS on your iPhone or iPad - Apple Support

Manually update your carrier settings on your iPhone or iPad

Manually update your carrier settings on your iPhone or iPad - Apple Support

Update your network provider settings manually on your iPhone or iPad

Update your network provider settings manually on your iPhone or iPad – Apple Support (UK)

If you see a Cellular, Ultra Wideband, or Apple Pay Issue message after an iOS update or restart

If you see a Cellular, Ultra Wideband, or Apple Pay Issue message after an iOS update or restart - Apple Support

I can't tell from your post. Do you currently have an active cellular number on your iPhone? Does it have international SMS enabled? Unless you have both of those things, you can't sign into iMessage or Facetime.