Can there something be done with the bill from €600+?

Dear Simyo,

This afternoon I got an email alerting me to the fact that my 13 year old daughter's mobile phone had been blocked due to a high bill. This evening I got home from work to find her in tears. She had just logged on to her My Simyo account after also getting the alert mail and seen a bill of over 600 Euros. How did she manage this? She had seen that she had data left for the month of September and decided to make use of it by doing a software update on her phone while at school. Bad decision… unfortunately she was not connected to the school wifi. 

She is devastated, realising that i can't afford this extra bill (3 children, single mum). Her solution is to find a job stacking shelves in the supermarket for the next 6 months but as a mum, I would prefer her to learn from her mistake and for her to be able to have time for her school work and sports. Is there anything that can be done to reduce this extremely high and unintentionally caused bill and prevent such a bill in future?

Yours hopefully,

Julia (mum of Marianne)