Hi
Have you checked your masts in the area or does no service happen everywhere ? Mast checker is
https://www.vodafone.co.uk/our-network-and-coverage/uk-coverage-map/On the iPhone hold down the Sleep/Wake Button and Home button together until the Apple Logo shows. Then On seeing this Apple Logo release both buttons ,and the iPhone will reset , which has been known to clear most glitches.
Other options are :
Settings -> General -> Reset -> Reset Network Settings.
If data is not working check your APN Settings in the iPhone to ensure they match the ones in this link
http://www.geeksquad.co.uk/articles/vodafone-apn-settingsDoes the iPhone work if you try another SIM card.
This is a process of elimination to see if it's the SIM card / account that at fault or the iPhone.
If another sim works in your iPhone then I would ask vodaphone to check your account and or perhaps re set it and to ensure they have you in file as using an iPhone so the data part works ok.
If another sim does not work in the iPhone then under the 12 months warranty you can ask them to run a diagnostic on it or if you have a local store local book a
https://www.apple.com/uk/retail/geniusbar/ appointment and if it's hardware issues typically swap it out in store for you on the same visit.
Current Phone >
Samsung Galaxy s²³ Ultra 512gb Phantom Black.