I've noticed a problem on the mobile web version of I am playing then like go to another tab to Google something after I have a few upgrades I can't interact at all with the game and have to restart my progress to get it working again
When I prestige and upgrade the upgrade costs i can get it to be 100% off but then that should mean it's free, why not just have the max be like 99% off
If you were to sell your characters because they were making to little for example, and you don't have enough money to buy another your just stuck and have to restart, I hadn't realized that and sold all mine