Clientele Legal - Refusing to Acknowledge Cancellations and Double Debiting

I took out a legal policy with Clientele Legal in 2011. I have not needed their services in that time. I had to complain about double debit withdrawals in December last year.

In early November, I decided that I no longer needed the service which had become very expensive and on 4th November, I emailed to them informing them of this. I did not receive a reply. I sent 3 more emails over the next month without reply.

On the 3rd December, Clientele debited my account. On the 11th of this month, I received an SMS saying that Clientele was going to debit my account early and this was done on the 15th of December, less than 2 weeks after the first debit.

I have repeatedly attempted to contact them over this, pointing out that this is double debit against the standards set out by the Ombudsman (Banking Services) in Bulletin 11. They have ignored all my attempts to contact them via email and their internet methods.

How do I get out of the clutches of these people?