SupplyMe review for Monster Cart Upsell+Free Gifts

Worst support we've received from any app provider over the past five years we've been on Shopify. The app was breaking our 'Add to Cart' button so that when it was clicked, nothing would happen. It would take quite a few clicks at times to add an item to the cart, and even then our old cart would load, not the MonsterUpsell version. I sent a screen sharing video to support regarding the issue, and they said they'd get back to me in 24-48 hours. 48 hours past, so I followed up to see what the status was. Here's the response I received, "Our dev team and even the head dev already checked the issue and tried their best to make our app work in your store. But unfortunately, we can't support your theme and therefore we can't do anything from our end." Disappointing for sure, but I was understanding, until I went to uninstall the app, and saw that the dev team chose to leave the app enabled on our LIVE theme when they knew it was breaking our 'Add to Cart' button. First of all, they should have been testing the app on a backup theme that was not published/live, and second of all, they should have immediately disabled the app once they confirmed they couldn't fix the issue. That's just basic, developer 101 type of stuff. It just shows how little they care about their customers. I'll be finding another in-cart upsell app, and I recommend you do the same.