US tax court notice?

We made some charity donation last year and got audited. IRS in brookhaven office asked us to provide receipts and cancelled checks copy. The letter was dated 12/13 and it says we have 10 days to respond before it is forwarded to US tax court. We received the letter on 12/16 and send out supporting documents (fax first then mail) the next day. 

However, today, we receive a US tax court notice to appear. The notice is dated 12/15. Anyone knows how to deal with this? Seems to us there is disconnect between departments of IRS.

Please help! On line waiting...

TONS OF THANKS!!