I don't understand the move. Seems it would be ultimately cheaper(support, potential legal, churn, etc) and harbor more good will to just flag these old accounts and leave them alone.
Most companies I've dealt with in the past just leave these older plans alone to rot, and try to motivate people off of them with new plans, new features, faster speeds, phone deals, etc. Not just arbitrarily deciding to jack up prices because "technically we're allowed to."
Most companies I've dealt with in the past just leave these older plans alone to rot, and try to motivate people off of them with new plans, new features, faster speeds, phone deals, etc. Not just arbitrarily deciding to jack up prices because "technically we're allowed to."