I guess you were originally trying to make a kind of Möbius strip type surface?

That probably will not work very well as one single surface with the edges you originally had touching each other - you can build such a thing using something like Loft, but it creates a surface that has a kind of opposite surface normal right along that edge, that will cause problems with commands that work off of the normal such as shell and offset.

You'll probably need to create something like that as a couple of different pieces, or leave a gap like you did in this most recent one and then add some little pieces in to fill in the gap.

- Michael