turn your back on someone

Despite their past friendship, he turned his back on her when she needed help.

尽管他们过去是朋友，但在她需要帮助时，他却对她置之不理。

I never thought he would turn his back on his own family.

我从未想过他会对自己的家人置之不理。

During hard times, their company chose to turn its back on loyal customers.

在困难时期，他们的公司选择对忠实客户置之不理。