Auto One Warranty Specialists Did not give me a full refund even though I cancelled before coverage began Irvine, California

I thought I had already done this report in 2007 but apparently not or it has for some reason been deleted. I purchased an extended warranty from this company on 12/11/06 with a $395 down and $144.87 for 12 months. After 1/15/07 I started noticing that people were complaining about their vehicle not being covered or Auto One not paying for service being done on covered vehicles so I called to cancel. After several tries and leaving voice messages with no avail I canceled my debit card before they could take another payment from my account. They then sent me a letter that the policy had been canceled due to non payment with a phone number to call. I called that number and told the person that I canceled the card because noone would return my calls. They offered to reinstate my policy with a discount but I declined. This person gave me a fax to send a cancellation letter to and I did just that. After 3 months of waiting for a refund I started calling again. The person I had talked to said it was being processed and just to wait. After 8 months I received a refund of only $143.22. That's $396.65 short of what I had paid and I want all that I paid back. This warranty was canceled 4 months prior to taking effect so I should be entitled to a full refund. I don't know what to do about the rest of the money they owe and am lost. Please help with any info you can provide.