Why must I pay AGAIN??

So a while back I bought Micro Battles. I had a lot of fun with all the games so I decided to buy the full version. $1.99 well worth I must say.
But recently I accidentally deleted the app when I was trying to make space on my phone. When I went to go re-download the game it downloaded just fine. As I opened the game it says that I es only allowed to play 1 game and that I had to repurchase the full version.
I honestly find it ridiculous, out of all the games Ive bought this is the first time Ive had this problem. Id appreciate if there was a solution, because apparently I am not the only one that has had this problem.

Cindaay10 about Micro Battles