I have just been on to T mobile Customer service.
After being cut off after 8 minutes on the first call I then rang back. I had to choose from option 1, option 2 etc 5 times before being put through to an advisor, (which means put you on hold listening to crap music until an advisor becomes available) 27 minutes in my case.
2 minutes talking to the advisor and I was told the phone was knackered and needed taking into store for them to send away.
I put the phone down then the phone switched on and now works fine.