Yup, same thing happened to me only, I sent in ⊗⊗⊗⊗ invoices. Once the appeal is denied you're pretty much burned. Although, did you ask them WHY the appeal was denied or WHY they were unable to verify the invoice? When I asked them WHY a senior analyst got back to me and told me that they called the number on the invoice and it did not match up  stupid on my part...But, since everything you send in was legit, I don't see why it would get denied, you should talk to more people get on the phone and talk to someone in charge.
__________________ “You have to learn the rules of the game. And then you have to play better than anyone else.”
-Albert Einstein |