WordPress theme may be overriding seo plugin

I have a website, http://myipodwontturnon.weebly.com , that I had put allot of time into. After finding out that I couldn’t change it’s title tag(constraints as a free user).

If you type in site:(my url name) in google, you can see duplicate weebly tags (“your own free website”). I moved onto wordpress in hopes to fix the issue. I was able to get my wordpress site hosted, allowing me to utilize plugins. There is a plugin called Yoast that allows me to change my title and meta display on the search engines.

What I am trying to get to is that I am having the same issue as I did with my site mentioned at the beginning of the post, where wordpress is constantly putting the sitename in my tags and metas. I read about the issue in Yoast support, and Yoast had mentioned that it could have something to do with wordpress default themes.

Could this be true? Is there a way that I can fix the issue? This problem made me have to remove 18 indexed urls from google and attempt to re-index them. Even now, after further tweaking of my plugin, I am still seeing signs of the site title pop up where it is not wanted. The reason that this is such a big issue is because my site is getting filtered due to duplicate content in google’s search engine.