@Hossain Belal: In order to unlock your phone for use outside the region it was intended to be used in, you will be required to make a 5-10 minute cumulative call to a local number from inside that region, using a local network SIM. If you are already based in Bangladesh, and if you have any friends or family in the region you purchased the phone, then you may wish to post it to them, so they're able to complete this process on your behalf. I appreciate that this may not be ideal, and apologise for any inconvenience this may cause you.
