Blog being spammed

Hi guys, my blog is being targeted with new posts in foreign languages appearing twice now in two days.

My website/ blog has undergone numerous changes in the past two weeks, these include:
- upgrade from Joomla 2.5.28 -> Joomla 3.4.1 (I upgraded Easy Blog to latest version here too)
- Upgrade of template from artisteer template to purchased template from Themeforest.
- Finally I updated my blog theme although I doubt this is to blame.

I notice the new blog posts, created by new bloggers (I never added them...) and then simply remove both, however this however does not fix the underlying issue.
If it helps, the intruders create new blogger accounts and posts however the rest of the website including my Joomla users are not affected in the least, which makes me think it is specific to the Easy Blog component.

My website address and blog are @ http://www.myebook.co.za

I would really appreciate your advice, i have looked through backend settings but cannot find anything obvious.

Warm Regards
David