Closure, if you choose to buy into this idea, is a trick. It forces you to go back into something you are no a longer part of to justify an action or reaction that already happened.
Why cause yourself, or the other person, more pain? Loss is loss and a breakup is loss. Time makes the pain fade and your blessed mind - your sweet, protective mind - will allow only the sweet memories to resurface.
Closure is your readiness to let the pain go and venture forward, once again. It's not about hearing something from or saying something to that other person. It's all about you.