You might consider modifying the current process of being locked out without any warning.
You current action creates much ill-will and animosity, followed by customer withdrawal, as noted in on-line forums; not something I would think you would want from loyal lifelong customers. If so then maybe I am with the wrong Company!
My suggestion is you have a 7 day continuous warning, renew in [countdown of days] or lockout will occur, at startup prior to renewal date and if renewal is not effected, then lockout would occur.
This will precipitate a conscious positive action by the user. If the customer does not renew then it might be advisable to at this point to ask for a withdrawal survey to be completed. You might also consider a length of time bonus for renewal; remembering that it costs a darn sight more to procure a customer than it does to retain an old one.
Note also that an unhappy customer will do your company more harm than good which again increases the cost of procurement and or decreases the number of uses, thereby affecting your bottom line.
