Cartly Cart Drawer Upsell

After some research the most straight-forward app with good design and customisation options. Unfortunately it messed with my cart and the whole site. Articles that were added / deleted didn't update, the entire page was slow and link reactions didn't work properly. When closing the slide cart underneath the so-far (theme) cart became visible. Customers were writing they almost hadn't purchased because the cart wasn't working correctly. So I had to delete it instantly. I wrote a message to the support team and if you manage to fix this I'd be happy to come back.