English Translation
Leave me alone.
This is a typical mistake made by native speakers. We don’t spell 1人 but 独り（also pronounced as ひとり）when it means “alone”.
Here is an article about the difference between 1人 / 一人 and 独り written by the professional proofreading team at Mainichi Newspaper (one of the big five national newspapers).
We use 1人 / 一人 when it can be grammatically replaced with another such as 3人 and 五人.
For example, “I have a wife” (私には妻が一人いる) can be replaceable with “I have three wives” (私には妻が三人いる). It’s grammatically correct, and also socially acceptable in some countries.
But you cannot say 私を3人にして unless it’s a line from an SF movie or human clone technology. So, 私を1人にして is wrong.
FYI: the original sentence was sourced from Tanaka Corpus, and adopted by a Tatoeba Corpus maintainer. She is a native speaker, but I found some of her other adopted sentences improper.