Non-functioning App

Couldn't manage to load data via the App on my iPhone even though I tried everything - loaded three different bank cards at the end but no luck - the App just hangs. Re-installed the Melon App a few times - still no luck. Customer support was excellent (they really went out of their way and tried to help - kudos to them) but technical support obviously was not. Deleted the App and e-sim as frankly, there are other options out there. Nice concept but it needs to work guys.