Although the game is very fun, it has had a record of deleting itself and making me pay again. I've payed over an hour of it normally, and now I'm comming back to it, and it's telling me to purchase it... I don't think I should need to re-purchase a game I've all ready purchased

Although the game is very fun, it has had a record of deleting itself and making me pay again. I've payed over an hour of it normally, and now I'm comming back to it, and it's telling me to purchase it... I don't think I should need to re-purchase a game I've all ready purchased