When switching my phone back on this morning only a black screen with normal signal icons at top. Windows 10 has gone! I cannot access Nokia Settings. If I touch the Back button, screen goes blue. Have tried removing and replacing battery and SIM Card, no change. The battery was and still is fully charged. Have looked into buying another similar phone but cannot find one anywhere. Have I been hacked? Just going to Bank to withdraw some Bitcoins.Any thoughts?