Безопасен ли boostmobile.com?

Long story short, someone gave someone else an old phone, that was through Boost Mobile. The customer had bought a new phone through the company. The person that was given the old phone, wanted to get the SIM unlocked. They told the man, that he needed to send them in email, the old customer's account PIN number. It was a clear attempt to breach the security of the customer's account.