If they try to lock me to them there will be a quick call to FCC. That's a NO NO. I purchased a Factory unlocked phone and actually AT&T tried it. It didn't work for them and I guarantee it's not going to for Boost either. They have been lying to the consumer for a long time. The biggest joke was when I asked the difference between the SIM card from one store versus the one they sent me to another store for was. Well you'll be 5G ready. I almost crapped myself trying not to laugh. I'll be dead and gone when and if Boost gets 5G.
Report it to FCC. If your phone is paid off or you do not owe Boost or any other carrier for that fact, they have to unlock the device that they should not have locked.