About how to unlock the SIM in H901

I had buy the T-mobile LG V10 (H901) from eBay and the phone is locked, I want to use it in Hong Kong.
The T-mobile IMEI STATUS is outstanding balance
How to unlock the phone ?
Does is work if I flash the ROM?


T-mobile IMEI STATUS CHECK:
"This device has an outstanding balance that must be paid or it may not be able to be used on T-Mobile network. "

imeipro info CHECK:
Brand: LG
Blacklist status*: CLEAN

imeidata net CHECK:
IMEIData Database: Maintain
AT&T (USA):
Verizon (USA): Clean (GSM or Activated by other User)
T-Mobile (USA): Unknown
Sprint (USA): Unknown
Cricket (USA): Clean
Metro PCS (USA): Clean
Telus (Canada): Clean
Telenor (Sweden): Clean
Softbank (Japan): IMEI is not recognized in Softbank
AU KDDI (Japan): IMEI is not recognized in KDDI

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