Upgrade to silver

Hi,

I´ve a simple question. Actually you have a promotion for upgrade to silver plan for 19.50¢/month.

We don´t have so much traffic, but we need a lot of forms. And we already made an upgrade to bronze on 2017/12/04. This upgrade is already paid.

Now my question is "what, if I do the upgrade to silver today? How much I have to pay (because a already paid 114 $ four weeks ago)?

If you upgrade, the amount you paid for a few days ago would be pro-rated and refunded, so far the usage is around $9.37, so you would get a partial refund for around $104 and you'll get a new charge for around $214