You can add data to your plan, but the plan must be active first. So, you'd need to put enough money on the account to cover the base $45 service fee plus tax. I think that if your account goes un-renewed or inactive, that the extra data and funds are forfeited. Any add-on data is good for 1-3 months as long as an active line is kept. To remedy this, you're going to have to Live Chat or call Verizon, or even visit a store to sort this out.
