Tried doing the update and it wont let me. As of now i am unable to text and use phone to call.

As of now i am unable to text and use phone to call.

Check ⤵️

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

If you can't make or receive calls on your iPhone - Apple Support

If you can't send or receive messages on your iPhone, iPad, or iPod touch

If you can't send or receive messages on your iPhone, iPad, or iPod touch - Apple Support

Tried doing the update and it will not.

If your iPhone is eligible for an update to iOS 15.6, you can check by reading this Apple article:

iPhone models compatible with iOS 15

iPhone models compatible with iOS 15.5 – Apple Support (UK)

Then go to: Settings -> General -> Software Update

See the following Apple articles:

Update your iPhone, iPad, or iPod touch

Update your iPhone, iPad, or iPod touch - Apple Support (IN)

If your iPhone, iPad or iPod touch won’t update

If your iPhone, iPad, or iPod touch won't update - Apple Support

You can do the update via PC, see this Apple article: Update software on iPhone, iPad or iPod touch in iTunes on PC

Update software on iPhone, iPad or iPod touch in iTunes on PC – Apple Support (UK)

If you have a Mac see this Apple article: Update your iPhone, iPad, or iPod touch with the Finder

Update your iPhone, iPad, or iPod touch with the Finder - Apple Support

You need about 7 GB device storage and good Service & Wi-Fi.

If they are On, turn Off Hotspot & VPN.