balance suddenly showing as zero on PAYG when i=big bundle due to renew

[hjw]

Every month I get a reminder that i need at least £10 balance to continue my Big Bundle. At round the same time, my O2App suddenly shows a balance of £0.00, having maintained a healthy balance of around £25-30 for the whole month. 

Last month, I panicked and put £30.00 on the phone, the balance then went up to over £50.00. It has now dropped to zero again.

This pattern is repeating every month. I am beginning to suspect that there is some unethical strategy to force unnecessary top -ups.

I do not have date roaming enabled and only use wifi. My package still shows a large amount of text messages and data available.

Anyone else getting this?

[MI5]

@hjw 

Must be a glitch in the system.

If you know you have credit, just ignore it as it sounds like it will correct itself after your bundle renews anyway.