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So by your own process of elimination your sim card and account to appear to be fine as they work in another phone.
Is this calls and texts to all your contacts or specific ones ?
If specific ones then please check your iPhones call and text blocking feature.
If it's everyone your trying to call and text then the phone maybe at issue or signal is poor. Check your masts current status by inputting your full postcode into this link > https://www.vodafone.co.uk/explore/network/uk-coverage-map/index.htm
Vodafone also offer an initial checks and template link to use and provide your answers back here in your thread > http://forum.vodafone.co.uk/t5/Network-queries/Network-issues-initial-checks-and-template/td-p/25405...
Try a reset by holding down the home button and power button together until the Apple logo appears and let go. For the iPhone 7 it's slightly different. A Google search would advise how and or use the Reset Network Settings in the iPhone. Hook up to iTunes to sync it.
An apple store genius bar would be able to run a diagnostic on the iPhone. If you don't have an apple store local then ask a Vodafone store to send it off if they actually supplied the iPhone to you.
The first thing to try here will be a replacement SIM from a Vodafone Store.
Sometimes a fauly SIM can work perfectly in an alternative phone but will have issues when used in a different phone.
If you still have problems with your calls and texts after the replacement SIM, please come back to the forum.