If it is one you'd specifically assigned to that device, the only option is to contact the manufacturer for the master unlock code. If that doesn't work, the phone would have to be sent in to have the memory wiped & completely reset to original factory settings, thus losing all contact phone numbers, photos, etc. Sorry to be the bearer of bad news; the other bad news is if the phone is over 1 year old or has a voided warranty (due to liquid or physical damage or unauthorized modification i.e. "jelly jewels", Glitterz, etc) you'll end up paying for that service. Hope this helps! =]
