This has generally been my experience also over the last few years.
I've actually asked Customer Relations about this before... They told me if you run into the character limit, just to submit multiple webforms, and they'll link them all together on the back-end for you.
If you're trying to contact AAdvantage Customer Service (for issues with your AAdvantage account, bonus miles, promos, etc.), then the number is listed on the website here:
http://www.aa.com/contactAA/viewCont...=AAdvantage%ae
If you're trying to contact AA Customer Relations (for issues with planes, crew, baggage, food, etc.), then just call AA Reservations, then have them transfer you to Customer Relations.