Blacklist

You may check the iPhone's serial number:

https://checkcoverage.apple.com/

Also see "How do I check for Activation Lock before I buy a used device?" here:

Find My iPhone Activation Lock - Apple Support

Apple will not be able to provide that information, as they don't "blacklist" phones.

That is a carrier function. Carriers can, at their discretion, keep devices off their networks.