I just learned about this the hard way today. So it looks like Verizon has removed the option to suspend your account through the settings on your iPad. A Verizon rep told me you either have to call them or remove all your Credit Card information from your account. If Verizon didn't like the no contract data service they should never have agreed to work with Apple.
Now I have to figure out how to get a Verizon store to give me a new sim card without locking me into a contract.
Now I have to figure out how to get a Verizon store to give me a new sim card without locking me into a contract.