Reading this I had a similar problem. I ended up resetting the four dashboard modules and the problem was fixed.
BO - Modules -> Dashboard (on left menu) shows the 4 dashboard modules. Click the dropdown on each and select Reset
Nemo has a blog post that works for preventing these types of spam. It was written for PS but I am using it successfully in TB 1.0.8 as an override for ContactController.php
http://nemops.com/blocking-spam-emails-in-prestashop/#.Xm7Zx6hKiUk