Currently, the balance shown may not be correct if you have not had a good internet connection since your last purchase. I’ve just come back from a trip in America where my signal was awful, and my Mondo app was telling me confidently that I had £100+ to spend when that wasn’t really the case - I was aware of it, of course, but it’s an easy thing to forget a small purchase and end up with slightly less than the app is telling you is there - possibly ending in a declined transaction, embarrassment, and the inability to top up (due to a bad connection).
So there’s a simple solution that would at least partly help - if the app detects a bad connection, it either hides the balance or warns that it may not be correct. I’m not a designer, so I won’t suggest how this could be done, but I know that it’d be a small thing to implement and could potentially be something that you guys haven’t thought of!