How to get my money from american express blue bird?

Certegy says they have paid a returned check that i deposited but amex says it was not?
Someone wrote me a check and i deposited it into my american express bluebird account via my iphone. The check came back as return and I never received my funds. The person that wrote me the check got a letter saying that certegy has paid there check to "american express travel." We have both been on the phone with both companies. Blue bird american express keeps saying the check was returned but certegy keeps saying that they paid american express. Now the idiots at Blue bird are in india and are not helpful. I have even offered to fax them documentation from certegy and they refuse to even give me a fax number. If I call any other american express department besides the one bluebird department they tell me that they can't help me and only that department can. The people at the bluebird department can't seem to simply just look up if certegy has paid them, they just keep trying to tell me that the check was returned and try to explain what that means. I'm not stupid, I know what that means but certegy says they have paid them and I even have documentation from certegy. How do I get my money from American express bluebird that they just have setting around in some system thats not connected to the bluebird department of american express?

Do you in fact have written proof from Certegy that they have paid the check? If you do, then go to the top of the food chain and write a letter to the CEO of Amex explaining your problem (no more than 1 page long) and include that proof of payment from Certegy. I have sent such letters to the President of Wells Fargo Bank (actually that one I hand delivered, though was not able to see him) and other large companies and got excellent results. No use fighting with peons. Here is the address:

Mr. Kenneth I. Chenault J. D.
American Express Company
World Financial Center
200 Vesey Street
New York, NY 10285
United States - Map
Phone: 212-640-2000