Idiom or phrase for "getting hatred/abuse after giving care to a person"

So what you want is a verb phrase that applies to the person receiving the abuse. Something like "got garbage as thanks for gold", except that that's no good because I just made it up.

"No good deed goes unpunished" doesn't quite apply because it's a whole sentence, and it's used when the person feels like that's the way of the world rather than particular ingratitude specific to a person.

"Bites the hand that feeds them" is perfect except that it puts the focus on the ungrateful person, rather than the victim of the ingratitude. Maybe that's OK, but it certainly can't be directly substituted.

I think the other suggestions so far are also not quite right for similar reasons, and unfortunately my best guess is that there is no such common expression. If one were common, somebody would have thought of it. When I have seen these situations in fiction, the victim might describe what they've done for the person and say "And this is the thanks I get?" This also doesn't fit as a replacement for your phrase, but it might be at least relevant.

No good deed goes unpunished:

Due to the cruelty, ignorance, or selfishness of the world or others, one's good deeds or good intentions will often result in more trouble than they are worth.

[The Free Dictionary]

You might say that they bit the hand that fed them.

bite the hand that feeds you to act badly towards the person who is helping or has helped you - Cambridge Dictionary

Here are a couple of examples in print:

• Everybody knows how helpful you have always been to her, but she bit the hand that fed her. - 1001 idioms to master your English

• Of Geoffrey's other illegal appointees to York, [M]r Erard, who had known Geoffrey when he was chancellor, also bit the hand that fed him, being a member of the hostile mission of the dean and chapter to Rome in 1194. - English Episcopal Acta 27, York 1189-1212