Please read below for more information about how the VIP program is supposed to work.
The VIP tiers do not stack. You will only receive the account modifiers for the VIP tier that is currently highlighted. You get to keep what is unlocked through the ranks, but you will not receive each tier as an additional +Max Energy.
For example:
In the photo above, the 3rd tier for VIP rewards is highlighted.
You can also see that Tier 4 is not yet unlocked. However, you can see that you unlock a new feature!
The next prize is "Increases Card Inventory by 65". Since tier 3 will no longer be active, you will receive 5 additional spaces for card inventory, not a total of 65 additional inventory slots.
Once you have unlocked a VIP tier, it will remain unlocked.