I need to get my erroneously blacklisted phone unlocked.

My phone was erroneously blacklisted while I was traveling in Canada last week . I have contacted Xfinity many times about this. The all first level support reps have been very courteous, and all have wanted to solve our problem, but lack the tools to fix this. When they escalate the inquiry to higher ups, the responses have not been timely or helpful. We have been without critical phone service for over 10 days now and upper management doesn't seem to care. Does anyone know how to get the attention of someone who cares and with the tools to get our phone off the blacklist?