Complex sentence: "Frozen" was not performed by Madonna until her Rebel Heart Tour in 2015, and on October 1, she performed an acoustic version of the song during the Detroit concert at the Joe Louis Arena.
Split into simpler sentences: Frozen wasn't performed by Madonna until her Rebel Heart Tour in 2015. However, on October 1 she performed an acoustic version of "Frozen" during the Detroit concert at the Joe Louis Arena.