I strongly suggest faxing any dispute letters. That fax confirmation sheet evidencing proof of delivery can be real helpful down the road. Here is the full text of the letters I sent. Feel free to copy or modify as needed for your own use:

Letter #1 (January 6):

Via Fax No. (623) 444-3000

Membership Rewards Correspondence Unit
American Express Membership Rewards
PO Box 297813
Ft Lauderdale FL 33329-7813

RE: American Express Platinum-Membership Rewards Bonus Points
Customer: XXXXX
Membership Rewards Program #XXXXXXXXXXX

Dear Madam or Sir:

I write today to obtain the 25,000 missing Membership Rewards points I should have received by meeting the minimum spend requirements on my new American Express Platinum card. On December 8, 2011 I submitted an online application for the American Express Platinum card. The offer called for me to receive 50,000 Membership Rewards bonus points after I spent $1,000 in my first three months of Platinum Card membership. American Express approved my application as evidenced by the attached confirmation page which clearly indicates under the “Welcome Offer and Benefits” section that I would get “50,000 Membership Rewards bonus points after I spent $1,000 in your first 3 months of Card membership”. Despite meeting the $1,000/3 months spend requirement, my Membership Rewards account was only credited with 25,000 bonus Membership Rewards. My multiple attempts to resolve this issue directly with American Express customer service have proven fruitless, so I am hopeful that you can quickly resolve this issue, credit my account with the missing 25,000 Membership Rewards points, and we can finally put this issue to rest once and for all.

If you have any questions, please contact me. My direct dial office line is XXXXXX, my cellular is XXXXXX, and my personal email is XXXXXX.

Very truly yours,


XXXXXX

Letter #2 (January 11):

Via Fax No. (623) 444-3000

Membership Rewards Correspondence Unit
American Express Membership Rewards
PO Box 297813
Ft Lauderdale, Florida 33329-7813

RE: American Express Platinum-Membership Rewards Bonus Points
Customer: XXXXXX
Membership Rewards Program #XXXXXX

SECOND REQUEST

Dear Madam or Sir:

Following on my correspondence of January 6, 2012, copy attached with fax confirmation, American Express has not provided me with the courtesy of a response to my inquiry and has otherwise failed to credit my Membership Rewards account with the 25,000 missing Membership Rewards points (for a total of 50,000 bonus points) I should have received by meeting the minimum spend requirements on my new American Express Platinum card. This situation is unacceptable. It is mystifying that American Express would make the calculated decision to breach a contract it prepared and agreed to and would otherwise expose itself to substantial legal liability over 25,000 bonus points. However, I can assure you that I will not rest until this situation is resolved in my favor. I would therefore appreciate the courtesy of a response and/or resolution in my favor no later than 5:00 p.m. this Friday, January 13, 2012.

If you have any questions, please contact me. My direct dial office line is XXXXXX, my cellular is XXXXXX, and my personal email is XXXXXX.

Very truly yours,


XXXXXX