P8 lite B574 vs Mobile data usage management

Hey there,
2 days ago, after i got back from a wedding, i was surprised to see i used to much mobile data and got billed from my provider.
So, because i do not want to happen again, i said to myself: "I'll set a data limit for mobile data". Well i can set a limit but i cant set the billing period.
My billing period is from 8th to 7th next month. Today i'm in 25th, my mobile data is OFF, and i don't know what to do. Where can i find the setting for billing period?

I got ALE-L21C432B574, no root, no custom rom, no custom recovery, just official updates. Any advice what to do?
If i wait to be on 8th August and set the Mobile data limit, is this gonna also create a hidden billing period?

I hope someone can help me.
Regards, V.

TUTORIAL - Huawei P8 Lite Android 6.0 Marshmallow B574 Root

Files:
1. BETA-SuperSU-v2.62: https://mega.nz/#!nJ9FXAjD!Jgelz-zLH...cNaPT-GD2ICsxA
2. SuperSU in System-Mode [v2.76-STABLE]: http://forum.xda-developers.com/apps...-mode-t3286120
3. UPDATE-unSU: https://mega.nz/#!3ZMCBDpJ!Lj9Fc1YMI...46ZNE-esov2Rbg

Process:
1. Flash TWRP 3.0.2 via ADB
2. With TWRP flash BETA-SuperSU-v.62
3. Turn off the phone
3. Again run TWRP and flash SuperSU in System-Mode [v2.76-STABLE]
4. Reboot the phone

That's all. Your bootloader must be unlocked!