I'm no expert, but I used to have an old Nokia. Their displays were prone to dissapear, but there is a simple fix, if it'll work. Take the phone and slam it against the palm of your hand a couple times. That always worked for my phone to get the display back. Eventually it will dissapear alltogether.

Regarding the networks, I do know from a reliable source that the new GSM network is not completely up and running yet simply because all the towers aren't installed yet. So the reception won't be good for a while.

Hope this helps some.

__________________

Current:
2014 VW Tiguan SEL 4Motion 43,000 miles.

2016 Hyundai Santa Fe Sport (wife's).

Past:
2006 Jetta TDI 135,970 miles. Sold Nov. '13.
1995 E-320 Special Edition. 220,200 miles. Sold Sept. '07.
1987 190-E 16 valve. 153,000 miles. Sold Feb. '06.
1980 300-D 225,000 miles. Donated to the National Kidney Foundation.
1980 240-D manual, 297,500 miles. Totaled by inattentive driver.