The app is only working on variant items, the non variant items it is not adding to the cart. emailed them several times, and tried contacting via chat. no response in 2 weeks!

Poor customer service. I installed and turned out that the app needed customisation to be compatible with another app. These guys DID NOT respond. Their online chat service is useless and their email service is even worse. Uninstalled as simply could not get them to reply to help resolve the issue.