Replaced the speedometer gauge panel

Bought a reprogrammed Speedometer gauge panel on eBay from a company and had it put on by my mechanic...but on drive home looked down and that company did not reprogram it, so it's 40,000 miles less than I need:/So frustrated. Called them and they said oh take it off, send it back and we'll put the right amount on there for FREE! What the @#$%!!!! Free? that's what I paid for! So they admit it was totally their fault. I told them I want them to pay the amount it cost to take it back off and then to put it back on. Said no, if I send back they will refund me, or they can fix it and refund me only $50 back for all the trouble. I don't trust them to do it right or perhaps even give me some crap back.

I got off Ebay from a company that seems to be the only ones to sell these reprogrammed panels for 2005. If I have this done at dealership they said I have to keep my truck there while they order the part and put it on so they'd be sure to get odometer amount correct, and I'd have to pay for a rental (so friggin expensive)! Dealership said they would not sell to me without putting it on.

Any suggestions where I could buy one of these things?

BTW: The part actually did help to get the check engine light off and the PO500 code off...so at least I know that it worked! The dealership said they would still want to do a diagnostic on it, even though I know this...and 5 months ago I went in and had a diagnostic and they couldn't find the reason.