regarding iMessage delivered label

Hello bharani49,

Thank you for reaching out to Apple Support Communities, and we'll be happy to help in any way we can. We understand you're having issues with messages and phone calls to a particular contact. If you see that your message was delivered, then it was. If you're unable to make or receive calls from the contact and you aren't blocked, try the steps listed here to see if they resolve the issue: If you can't make or receive calls on your iPhone

"If you can't make or receive calls on your iPhone

Find out what to do if you see "No Service" or "Searching" in the status bar. If you can't make or receive calls on your iPhone, follow these steps, testing after each step:

Contact your carrier

When you contact your carrier, make sure that:

• Your account is set up to use your iPhone.
• There aren't any localized service outages.
• Your account doesn't have a billing-related block.
• Your calls don't have errors on the carrier system.

Update your software

1. Check for a carrier settings update.
2. Check for an iOS software update. Some updates might require a Wi-Fi connection.

Check your iPhone settings

1. Turn Airplane Mode on and off. Go to Settings and turn on Airplane Mode, wait five seconds, then turn it off.
2. Check Do Not Disturb. Go to Settings > Focus > Do Not Disturb and make sure it's off.
3. Check for any blocked phone numbers. Go to Settings > Phone > Blocked Contacts.
4. See if Call Forwarding is turned on. Go to Settings > Phone > Call Forwarding and make sure it's off.
5. Check to see if Silence Unknown Callers is turned on. If the setting is on, a caller must be listed in your Contacts or Recents. Or they must have shared their number in Mail or sent you a message using that number in order for their call to go through. Add their number to Contacts to ensure the phone rings. Calls from some third-party apps might not go through.

Check your network settings

1. Reset your network settings. Go to Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings. This will erase all current saved settings, including Wi-Fi passwords, preferred networks, and VPN settings.
2. Try to make or receive calls in another location.

Contact Apple Support

If you still can't make or receive calls, contact Apple Support, then follow the steps to complete your request."

We hope this helps.

Cheers!