I'm afraid I could not find one either, and when I used the regular customer service email address I got random responses that did not address my complaints. They only way to add to the complaint deluge is to write to the only place where the efforts will count: the CEO (in reality it's his Administrative staff that will see it, but will summarize it to him). Here you go:

Mr. Bruce Hammonds
MBNA Corporation
1100 N King St
Wilmington, DE 19801