Your account was suspended due to use of third party programs over the course of the last 3 months, which is against the Terms of Use:
Blizzard Entertainment: World of Warcraft Terms of Use
When running, the World of Warcraft client may monitor your computer's random access memory (ram) and/or cpu processes for unauthorized third party programs running concurrently with World of Warcraft. An unauthorized third party program as used herein shall be defined as any third party software, including without limitation any addon or mod, that in Blizzard Entertainment's sole determination:
I. enables or facilitates cheating of any type;
II. allows users to modify or hack the World of Warcraft interface, environment, and/or experience in any way not expressly authorized by Blizzard Entertainment; or
III. intercepts, mines, or otherwise collects information from or through World of Warcraft. In the event that World of Warcraft detects an unauthorized third party program, Blizzard may
a) communicate information back to blizzard entertainment, including without limitation your account name, details about the unauthorized third party program detected, and the time and date the unauthorized third party program was detected; and/or
b) exercise any or all of its rights under section 6 of this agreement, with or without prior notice to the user.
The use of such programs or files is clearly unfair to the World of Warcraft community playing regularly and is not tolerated on our servers.
Following a review of your case, we can confirm that such programs have been used on several occasions by your account, and that the subsequent action taken is appropriate. We would not look to enter into any further communications on this issue as the matter is now considered closed.