Mind your own business.

Literal

Unnecessary meddling [topic-は] stop-it!

A blunt, casual refusal: 余計なおせっかい ('superfluous meddling') is the topic, and よせ is the rough imperative of 止す ('to stop/cease'). The idiom here is the whole complaint-frame — marking the speaker's annoyance at unsolicited help. よせ is sharper than やめろ and carries a 'knock it off' register; use it with familiars or subordinates, not with strangers.