I regret choosing Vodafone as my carrier. I wrote an email to Vodafone CEO twice and they promised they will provide me new handset, but they keep sending the handset to repair centre. Worst customer service ever.
Another route if you have a local store is to make a https://www.apple.com/uk/retail/geniusbar/ appointment and if it's hardware related they'll replace it in store for you.
Make a backup to iTunes and or iCloud before you go.
