It's AmEx and I am planning on suing them for calling me @ 6:33 A.M.

I called number 866-300-3420, Identified them self as American Express and asked me to input my account number. I didn't and was connected to a voice mail box to leave a massage, with account number.  I didn't.
I called AmEx, number on back of card. Rep said he would check on the number and put me on hold. Came back saying it was indeed a AmEx customer service number. Then went on to say he called it and person identified them self from AmEx. I asked if it was truly an AmEx number and he said actually not sure. He was going to pass it along to supervisor. He said my account is in excellent condition so nobody should be calling. He said to disregard the call and AmEx would take it from here.
I think it is a third party company that works with/for AmEx trying to offer me another card or service. Time to read AmEx privacy policy again and see who they share information with.

called twice on Sunday 3.29 @2:40 p,

Called asking to lower my credit card interest rates and tried to
get personal information about my credit card accounts. (Said they needed the info in order to lower my rates). Tried to get me to apply for a PLUM CARD, don't even know what that is but it soungs gross !!

This phone number is American Express bill collectors.  They seem to have hired a new crew of marginally competitent people (not the usually uppity American Express people) and they all sound like idiots so it's easy to question their legitimacy!

wish they would stop

Got a call from these ppl on April 13, 2010, at 9:47 am, tho i missed the call, due to being in class at that time. Problem is, i dont even have a credit card. If its from American Express, they need to speak with my parents, not me.

I called AMEX and this number is not even in their system.

You are a FRAUDSTER, Maggie, and you are posting here to try and sound legitimate so people will be fooled by you scammers.
Listen folks, if American Express, supposedly, calls.  Say that you will verify that American express or Capital one, etc. are calling by calling the number (1-800- ) usually, on the back of the credit card you have in your possession...that way, you know who you talk to before ever giving any personal information.
These calls are fraudulent:  same jerk keeps asking for a Mr. Pepperona, and guess what?  It's not me, and it's the same surname asked of other people in different states???  These fraudsters aren't very imaginative.
Call the number on your credit cards, or wait for the LATE or DELINQUENT letter that always comes from an official credit card company when they inquire, as they know about these scams and so generally contact you this way, at least eventually.

SCAM.
They're still calling and leaving 866 300 3420 as of 05/06/2011
They cant enunciate. Either they've been drinking or English isnt their mother tongue.
I havent had an AMEX in over 20 years.