Complex sentence: Between 2009-2011 I used different user pages and names, however, I never used two pages/names concurrently... and after beginning to use a new page/name never went back to a previous user page/name.
Split into simpler sentences: Between 2009-2011 I used different user pages and names. However, I have never used two pages/names concurrently-and after beginning to use a new page/name have never gone back to a previous user page/name.