No contact number or refund policy??

I signed up to the 30day free trial for Prezi not realising that you would automatically start direct debiting me once it ended.

I have been debited £108 ($159). I did not want to pay for this and would like to know your refund policy to get the money back. I have searched your website and cannot find a contact number to speak to someone, nor can I find the refund policy.

I also do not understand why it is so much? Colleagues and friends who use Prezi have only paid £59 for the program.

I have cancelled my subscription but hope you can help me with the refund situation.

Thanks in advance
Kate