Please try to flash your phone with the download flash rom BV6000_Blackview_V01_20170517
https://mega.nz/#!ZbhE2bJS!GwxZGnTsqYfy ... DZXOlxjSAkAnd after flashing, do the factory reset, below is the way of factory reset.
"Start the phone into recovery:
- Press Power and Volume up together for around 10 Seconds
- When the open android is shown press Power and Volume up together again
- Select Wipe data/factory reset with volume keys, confirm with power
- After factory reset select ""reboot system now"""
If still can not fix your problem, you can contact at
dimitri@d-sign.be.