For your information, investigation into hacking falls under the jurisdiction of PDRM and action can be taken under the Computer Crimes Act 1997. Reports can be lodged at any nearest police stations.
You are also encouraged to lodge reports to the operator of the blog or website. Most websites provide abuse report service including hacking. Possible actions to be taken include removal of the affected account or password reset.
Example: Complaints to Facebook
Go to this link : https://www.facebook.com/hacked
Example: Complaints to Twitter
Go to this link : https://support.twitter.com/forms/signin
Example: Complaints to Yahoo Mail
MCMC would like to advise you to raise reports directly to Yahoo web operator at https://edit.yahoo.com/forgotroot/, because report from the affected person is preferred by the Yahoo administration.
i. After clicking the link above, a main webpage about reporting issues related to your Yahoo account will appear.
ii. Then click on My account may have been compromised
iii. Then press Next button
iv. And then follow the instruction provided and fill in the needed details until completion.
Example: Complaints to Wordpress
MCMC would also like to advise you to lodge reports to Wordpress website operator at http://en.wordpress.com/abuse/, because reporting by the affected person is preferred by the Wordpress administration.
You can complete the complaint information form provided by Wordpress according to the following steps:
i. Fill in the complainant real name
ii. Fill in formal email address of the complainant (the email address will be used by Wordpress to contact the complainant for further feedback)
iii. Select Type of Complaint – Other
iv. Fill in the URL of offending blog post
v. Answer Complaint (please provide the specific quotations of the offending material)
a) You need to explain that your Wordpress account was hacked by someone for the purpose of, for example, tarnishing the complainant's credibility.
b) Inform them that the defamatory content as specified in the link provided above had led to major problems to you/your organization (provide examples of such problems).