but, is it their fault that the product they sell and you bought doesn't work the way you want it to?
did they misrepresent any facts? did they tell you it would work?
what i'm sayin' is, if you bought something from them with the intention of using it in a way it wasn't designed for, it's your mistake, and they have no legal (or moral) obligation to refund your money or take responsibility for it.
you should see the pile of parts i have laying around because i thought "hey, this just might work..."
if you were cool to them, they might take it back and refund your money, but after 6 months of emails, they probably don't wanna deal with you anymore. i'm willing to bet they weren't the friendliest of emails on your part.
just sell it on ebay and cut your losses, and next time, do a little more research.
sorry if i'm coming off a little harsh, but the whole "the customer is always right" attitude is nonsense. they did their job by getting you the part you wanted. it's not their fault you can't use it.