got 1 of them sim card where you top up £10 a month and then put a tenner on it, had o2 ring me up ask me loads of q's which i answered i put £10 on it but then had to goto germany for a week and just got back (left phone at home off)

when they rang me up i said no to the HOME100 offer yet ive got 2texts saying its been activeated and 9.99 has been removed form my account


and now my balence is £-4.68


What shall i do? their helpline is like 50p a min