I Phone XS new keeps dropping out

[CW22]

Hi just got new IPhone XS from 02 on contract and when I got it back my calls kept dropping out.  People said they couldn't hear me and/or it sounded like i was underwater, or the calls just failed.

Helpful man at Trinity Leeds 02 changed the phone for another new one and within a few days same problem was occuring.  They then changed the sim card and sadly it is still happening so am having to ask people to call me on my landline not great really...

Just wondered if anyone else had this problem and if so how was it resovled.

They have offered to exchange to a third phone if I take back before the four weeks is up but just not sure why it's doing this and wondering if the XS has problems?  Also can't get Twitter ap to work on phone either so not sure if bug?  The 02 store did transfer of my data on phone through their computer to my new phone.

I've emailed 02 customer services but they say that it might be 5 days before they respond.

Any ideas anyone?

Thanks

[MI5 · Accepted solution]

@CW22 

Just exchange the phone again as you appear to have been unlucky twice.

No reason why Twitter shouldn't work either so you might be best to set up new phone as a new device then restore your own backup from iTunes. 

Maybe there is a corrupted file in the data being transferred so far?

[Anonymous]

Somethings corrupted somewhere. Possibly the iOS backup