do good but regard as ill will
The Chinese idiom, Pinyin, is w é IH à och é nqi à n, which means that if a good heart is not rewarded well, it will be kindness as revenge. It comes from the warning of the world by Feng Menglong of Ming Dynasty.
The origin of Idioms
Feng Menglong of Ming Dynasty's "general admonition of the world" Volume 21: "it's a crime of slavery not to repay the benefactor's virtue, but to punish the benefactor's pure name and to apologize for his kindness."
Idiom usage
A good heart is not rewarded well
do good but regard as ill will
climb up high mountains and cross vast seas - zhàn shān háng hǎi