Brought a L1520.1 Yellow today. been on charge for 30mins and its just been booting to a blue flash then off. and keep repeating it over and over again.
I would suppose returning it to the store is not an option? Personally it better work perfect right out of the box before I even decide to key it. My first one locked up playing a video 3 hours after owning it, it went back to the store. You could try to hard reset it.
You could try a hard reset, without booting the phone.
Google Lumia 1520 Service manual - there is a key combination which will hard reset your phone.
READ, then execute - that's Y I referenced the Service manual instead of giving you the key combination !
You should wind up no worse than now, possibly better.
Its working on two months with no response from him so he's probably long gone. Or he figured it out and hasn't come back because he needs no more help for now.