Tow Company Increased Invoice For Insurance—how Do I Get My Reimbursement?

A couple of weeks ago, I had to get my car towed after getting stuck in a ditch. The tow company charged me $400, which I paid at the time (I have a basic receipt for this). My insurance, GEICO, covers towing reimbursement, so I submitted the receipt. However, they told me they needed a more detailed, itemized invoice.

When I went back to the tow company to request this, they rewrote the invoice for $900 instead of the $400 I originally paid. When I asked why, they told me the $400 was a “deal” and that they were now listing the “retail price” so GEICO could “even out their pocketbook.”

GEICO will likely reject this inflated invoice, but I just want my $400 reimbursement. What’s the best way to handle this? Should I push the tow company for a corrected invoice, or can I get GEICO to accept proof of my actual payment? Is this kind of price inflation even legal?

This is in Oregon if that matters.