"Why do they not visit you?"
Translation:¿Por qué ellos no te visitan?
The "no" is always coupled with the verb and the subject does not come between them. The subject precedes no (and nunca) in this kind of sentence, and you will often see the subject follow the verb when the sentence is preceded by an interrogative word/expression such as Por qué, cuándo, dónde, qué (etcétera).
The earlier question about grandmother visiting doesn't accept subject before verb.... This one has subject before verb.... Why is one correct and other incorrect? Both begin with question word.
I am quite unsure about using the phrases a ellos, a usted, a el and the likes. I tried to say "por que no te visitan a ellos" (don't mind the accents). I would like to know the reason this is wrong and the rules for using a ellos etc.
since ellos is the subject, it does not take the personal a. Por qué ellos no te visitan is one way to word the question, or Por qué no te visitan ellos
why can't I use "se"? Por qué ellos no se visitan. What is wrong with that?
To say "you," you want the direct object pronoun: te (for tú), lo/la (for usted), or los/las (for ustedes).
"Se" changes the meaning of the sentence to something along the lines of "why don't they visit each other, or themselves, or why aren't they visited?"
Doing some experimenting. I tried "¿Por qué no ustedes visitan ellos?" and was marked wrong. Later I tried "¿Por qué no te visitan ellos?" and it was marked correct. OK, I think I get it. Plural informal you should have been os. "¿Por qué no os visitan ellos?"
The first sentence you gave was incorrect because ustedes came after no and should have come before it. I know people often say that placement doesn't count as much is Spanish as it does in English, but I find that placement often does matter. Good for you for experimenting, though. Best way to learn.
My intention was to use plural you as the object. So it was not a word order issue but a word issue. Should have been os instead of ustedes.
Thanks for the comment re experimenting. It is fun to do at times but gets me marked wrong a lot. Nothing wrong with that, though.
I am wondering why it can't be por que ellos no visitan contigo..why dont they visit with you?