How do I remove overlapping faces for this case? Thanks for your attention!

I imported a svg image, extruded it, did the shortcut 'I' thingy.
Now I have those overlapping faces in corners.

I tried 'remove doubles' but it didn't remove any verticles(tried merge distance as well). Merge didn't do the job properly either.

How may I handle this? 
I want to extrude the inner face after organize the border part faces.

It would be lovely to have some advice long or short!
Thank you in advance. Wish you a lucky day :)
First of all you need to select the inner ring that you created with I. You can use Alt for it. Then deselect everything that is fine with the circle selection tool (C). Then press X and select Edge Collapse. Your problems should now be fixed. For that selection part I made a little picture here:

Just deselect everything which is outside the problem area.