Caveat Emptor. You paid for precisely what was available at the time of purchase. The engine is free, you bought/buy modules having received, and presumably tested, the base product for free. If you thought that it was bad then why did you throw more money at it with the hope that it would some day meet your expectations?
This is entertainment, if it doesn’t entertain you then do something else. Time is precious, it’s not worth getting this wound up about a video game.