It does not work good

I wanted to try this plugin and installed it.
After this I activated it and put it on my sidebar.
It was not that what I was looking for and deleted it on the widgets, but it doesn′t remove from the website. So I deactivated it and nothing happened because it was still visible at the frontpage.
So the next step was deleting this plugin but it was still visible on the frontpage. I tried to clear my cache but nothing happened and it get a worse looking on the frontpage.
Definitely bad working at this time!