When you Upgrade or Downgrade your Opensolr account, regardless of the recurring period, all Upgrades and Downgrades, are always pro-rated, so you always only pay for the calculated difference from the unused days of the existing membership plan.

This also applies in case one of your recurring charges has been rejected, and you chose to place a new order, instead of updating your biling information.
Please refer to updating your billing information to learn more.