Myiq.com Unauthorized Charge After Trial Subscription

Today, an amount of £39.99 was taken from my bank account by Myiq.com/US without my authorisation. Two weeks ago I only purchased a single report for a small fee after a one-time trial, and I did not knowingly agree to any ongoing subscription or recurring payment. I request that this apparent subscription be cancelled immediately, that the £39.99 taken today be fully refunded to my account, and that I receive written confirmation that no further charges will be made without my explicit consent.