Welcome to the community!
You should note that, depending on method of payment, it can take a number of days for payments to be received by Fido (see here). You mentioned you made payment through your bank app so it may take approximately 5 days for it to be processed and received by Fido. Once Fido does receive payment, it should be reflected in your My Account balance.
Since it can take a number of days for payments to be processed and received, it is important to remember to leave enough time for them to be received by the required due dates.
Hope this helps 😀