I am not a native English speaker, but this negation construction without an auxillary verb sounds a bit archaic to me. The point is: the best translation is not the one, that translates every single word literally, but the one that expresses the same content with the same connotation/style/etc. in the same context.
I've used it in speech several times in the last five years. It should be accepted. Also, we don't know the context, one of Duolingo's biggest flaws. There isn't a "best" way to say it because we don't know what conversation or event took place to make someone say this phrase.
English negation can sometimes go at the end of a sentence. In this case the rest of the answer ( in brackets) has been dropped
Do you have a lot of money? I do not.......(have a lot of money)
Have you borrowed money? I have not...(borrowed money)
Are you happy? I am not..............................(happy)
Here are some rather snarky, slightly archaic answers.
Do you think so ? I think not !
Do you not care !? I care not !
Whilst pulling the petals off daisy you often repeat the following about your crush... "He loves me, he loves me not."
But english negation otherwise comes up front. As a island folk we like to let you know the bad news early so "You help me not" is not in common use and sounds a bit like Yoda.
We are more likely to say "You are NOT helping !!!"
helfen requires an object in the dative case.
There are a number of verbs whose object is in the dative case; some of these are helfen, danken, folgen, gefallen, gehören, antworten.
It's just something to learn; there's no logic why the object of helfen should be in the dative case rather than the accusative.
In addition to what mizinamo said, please also take some time to read through the articles in the 2 links below -
I found them quite useful !!
I am unsure if the messages asking to show a mistake are directed towards my initial post. If so, I am not posting regarding a mistake. I am posting for clarification. The English sentence 'you are not helping me' can mean that the actions of the person offering assistance are not helpful, or it can mean I will not allow you to help. I am writing to ask which meaning the German sentence implies. Thanks.