If you have topped up and the payment has left your account and not gone onto your meter, please don’t panic, your payment won't be lost.
These payments are being ‘held’ by your bank and will be refunded within 3-5 working days - but it might be sooner, depending on your bank. The payments will show as pending on your bank statement.
If this happens, please try deleting and reinstalling the app. You can download the app by searching 'Boost Top-Up' in the App Store or Google Play Store. This will often iron about any issues, as it’ll make sure you have the most updated version of the app.
You’ll find lots of handy info here.
I hope this helps!