The Rocket Man hitmaker, who battled substance abuse problems of his own in the past, was asked by Houston's aunt Dionne Warwick to step in after it became clear the singer was struggling.
However, the music legend reveals Houston refused to take his calls, and he was devastated when she was found dead in a bath tub at a hotel in California in February, 2012.
He tells Britain's Event magazine, "Dionne (Warwick), her aunt, kept asking me to try and get through to her, to speak to her. I tried, I left messages for her, but either it never got through or she just didn't want to call me back. I listen to her voice (now) and just want to cry."
Houston had a long history of drug problems, and her death was ruled an accidental drowning, combined with the effects of heart disease and cocaine use.