Yes you can. To do that:

  1. Sign in to your Reseller console.
  2.  From the left pane select the Upgrade option.
  3. Under Additional Cold storage,  check the box next to Add cold storage → From the drop down menu, select the amount of Cold Storage you want to purchase.
  4. To purchase Instant Storage, check the Add Instant storage box → Select the amount you want to purchase.