"Your account is inactive."

Greetings,

I have a query regarding posting on the forums with my account. Whenever I attempt to log in, I am unable to select any characters to post with and am met with the message: "*The characters on this account are unavailable, as the account has expired or is prohibited from posting."

As far as I know I have not been banned from posting. I haven't received any e-mail from Blizzard regarding any derogatory posts that I may have made. Furthermore, my account still has plenty of paid time left so I can not see how my account is deemed 'inactive.'

Any help on the matter would be much appreciated.

(P.S: I am referring to my other account not this one ofcourse ^^).