First, I don't want to be alarmist, keep in mind my bad english.
But:
Voice and internet dataplan with Orange Spain.
Still 306 of 600 min., of wich 103 of 300 min. for mobile to mobile calls.
Still 57 of 500 mb (yup!), anyway, when limit reached, conexion slow-down, no overcost.
No sms sent.
No mms sent (LOL).
No change of plan, NOTHING. Period.
The fact: 5.81 € overcost from 23 july until today... detail of this month calls, shows nothing. But the money is there.

Orange issues? Possible, but please, check your bill this month.
We could have some bad-boy-deb in the town.
Regards.