PageSpeed & Image Optimiser

I’m not going to give them a 1-star as some did because that seems petty. The app seems to work, although I’ve been trusting their analytics to tell me that. My concern is that they have "usage charges," but I have no idea what they’re for. I searched both the FAQ and documentation for "usage," but got nothing. I sent an email asking, but never got a response. I see a number of other reviews that mention this too and, for the record, I’ve checked my junk mail folders. Because of this and the general need to cut back on paid apps, I’m uninstalling

The app stopped working 3 weeks ago, blank screen. Cleared cookies, cache and even changed browser and still does not work. Tried in a different store and and it works just fine. So the issue is only in our store... Being reaching Clauma support via e-mail and via Shopify form and no answer for 3 weeks already, the app used to work fine but the issue and the lack support will make me delete it. Would not recommend right now.

UPDATE: After some months it seems that support has reappeared and the app has being updated. It now works as expected.