I would like a refund on an iTunes subscription charge.

I would like a refund on an iTunes subscription charge for MileIQ. I had initially purchased a monthly subscription for the MileIQ Unlimited plan, but then they emailed me an offer to purchase a yearly plan, directly from them, outside of the iTunes store. I was then charged for their monthly fee after that purchase. They (MileIQ) have absolved themselves of any responsibility for the charge or for getting me the refund.