I had my account frozen because they claim that I ...

I had my account frozen because they claim that I hadn't used
the phone for 6 months,something I strongly dispute.To restore
the balance I topped up and called them back.But they asked
me a series of "security questions"which were almost impossible
to answer.eg what was the amount of my top up 6 months ago?
Or,which foreign country had I called the most.Then to add insult
to injury the operator spoke at a soft level that I could barely
understand.