Pumper Bundles Quantity Breaks

The app simply doesn't work. I've spent weeks in the chat trying to solve my problem but they have no idea. I've created quantity discounts on my website. A customer will purchase multiple items that should qualify for quantity discounts and they get maybe 1 or 2. I've rebuilt everything and promised that "it's fixed" multiple times with no resolve to the issue. I really wanted this to work but ...

I've had this app break multiple times just out of nowhere and I've lost literally thousands, any other app won't break like this and cost you, so be very careful, also it's very basic compared to others.

The app has a bug on volume discount, I setted buy 3 can get discount, but when i buy 4, all of them can not get any discount. And they can not fix