In one way this doesn't make sense to me.
e-mail and PIN rely on the cell phone network (or at least redirection from the cell phone company)
If your service is cut off, SOME wi-fi stuff will work. I had the same expereince on my old phone before work started paying my bills. Wi-Fi should work on the browser.
I wouldn't expect e-mail or PIN to work at those use the cell network and are associated with your phone/data plan, which is cut off.
Pay up :P