bookschristian.com $430 refund check still not issued after 8 months, Internet

In August of 2010, our church placed an order for more than 100 books. Three weeks later, the order hadn't even been shipped, and we needed them for an event, so we bought them elsewhere (and had them three days later) and sent an e-mail requesting that our order be cancelled. Two weeks later, the books arrived, despite the cancellation e-mail. I shipped them back (at the church's expense), and was promised a full refund for the cost of the books. Then I got an e-mail saying that I only shipped back 20 of the books, and would only get $100 back instead of $400. I responded with tracking numbers showing that they signed for all three boxes. The books magically reappeared in their system and I was once again told that I would get a full refund. That was 8 months ago, and despite e-mails every six weeks, the check has not been sent.