I was using the C1 Mobile app on my iOS devices, one was iOS 9.0 and another iOS 11.3 and was working fine, and is still, but sometime while the app is opened for more than a while of around 20mins+ it is getting frizzed and crashes in 9.0
Thank you for bringing this issue to our attention. We have tried replicating your reported issue in our iOS 11.4 and after some time (20+mins) the application is still running and we are able to navigate to it.
What we recommend is for you to update your iOS to the latest version if possible. If not, we will have this case escalated to our development team for investigation.
Please let us know your feedback.