turn your back on somebody/something
turn (one's) back on (someone or something)
To ignore, disregard, or exclude someone or something; to abandon, give up on, or forsake someone or something. It's clear that the company has turned its back on customers. After becoming a successful writer, Jim turned his back on all the people he used to know back home.
turn your back on something
COMMON If you turn your back on something, you reject it or stop being involved in it. He had turned his back on his Communist past and formed a completely new party. The organisation says that young people are increasingly turning their backs on marriage.