I have made a server and VIP automatically gets 3 rows of backpack storage, how can I make it to if they go on the tebex store it wont just grant them the 1 row permission but rather the 4th row permission, if so is it possible to just make one package if they purchases it over and over it just stacks instead of giving the same 1 row permission?

That feature is not currently supported by the plugin. I have a notion of how the plugin could do this, but it would require an entirely alternate mode of the plugin which stores a number for the player's capacity rather than simply using permissions for determining capacity.

For now, you will need to design your store to have separate purchasable packages for each size.