Roaming charges being activated

[Katapls]

don’t understand what activate a rooming charge, my data mobile has been off and only used my mobile with WiFi. I wake up today at 7 :30 to find out my roaming passport plus has been activated. How? I did not used the mobile, I was sleeping. . It is the third time that happened. I switch off mobile data so I don’t have any charges and this happens

[PandJ2020]

Switching off mobile data roaming is not enough.

Your device will still be connecting to the cellular service.  (And the passport can be triggered)

Put it in airplane mode.