Complex sentence: Deni had some minor success in the 90's, since then her singles have not charted in a last ditch attempt to stay relevant she played the "shock-jock" bully contestant on the Australian reality series Celebrity Apprentice.
Split into simpler sentences: Deni had some minor success in the 90's, since then her singles have not charted. In a last ditch attempt to stay relevant she played the "shock-jock" bully contestant on the Australian reality series Celebrity Apprentice.