I transferred my number from optus to a new TPG mobile plan and activated the sim. When I inserted the tpg sim, I get a pop up saying "NETWORK LOCK, you are using a carrier-customized phone,SIM cards from other carriers are not supported on this phone. ...."   My old optus sim doesn work and the new tpg sim doesnt work... How do I unlock the device? Please help   Thank you ... View more