Best answer by Ed_Boost
We always advise deleting and re-installing the app, which sorts any issue out 9 times out of 10.
You can always top-up using the card you should have received (a black one with 'Energy Payment Card' written on the front).
If you're still having issues with the app, you'll need to get in touch to let us know, so we can get this sorted for you. You can send an email to hello@boostpower.co.uk, or send us a message to our Facebook or Twitter pages.
Cheers!