Cell C IPhone X

Upgraded my contract end off June 2018 to an IPhone X, one Wednesday 21 November the phone started going on and off, we checked everything and noticed that it’s busy with an update but keeps switching off while busy so it can’t finish. We went to Cell C highveld mall and explained everything to the lady, she referred us to the Istore. On Sunday 25 November we went to the Istore they could not assist as the warranty is with Cell C were we did the upgrade. We than went back to Cell C to book in the unit, as per the Gentleman that assisted us he cannot retrieve the phone on the system and need to request from head office as they don’t have manual procedures in place and said we have to come back Monday when we arrived at the store on Monday he said that he did send the email and he is waiting for a response and that they will say if they will repair or not. Currently we can’t use the phone as it still switches on and off every 3 min, and need the phone for work as there is no loan phone available either. The phone is barely 5months old so we would rather want an exchange than for it to be repaired.