This may be for 1 of 2 reasons:
1). Your credit card has expired - please register a new credit card in the My Account Portal
2). You have exceeded the limit of 4 top-ups in a 30 day period - by default we only allow up to 4 credit card transactions within a 30 day period. This is a measure to prevent credit card fraud & protect our customers.
For example, if the first payment is on the 2nd of February, then the second one is on the 12th of April, the third is on 16th of April and the fourth is the 18th of April. If your credit runs out after this 4th top-up, you will need to wait until the 2nd of May (30 days from 1st top-up) for the top-up trigger to be reactivated.
Alternatively, you can top-up your MyNetFone account at any time over the phone by calling our Customer Service team on 1300 731 048 Mon-Fri 8am-12am AEST or Saturday 8am-8pm AEST.