Without seeing them, it sounds like you have been sold an infected plant with 'Red Spider Mite'
So I'd guess and say, bad guys.
Are they mostly on the under sides of the leaves with fine webbing ?
These mites are harmful to plants (sucking on sap) and thriving in dry indoor conditions.
It you've only just bought it, it may be worth returning it and complaining. you may be offered a replacement.
Otherwise it can be treated with chemical sprays, that can be purchased, specially for the job, as directed.
To keep plants clear of r.s.m. a regular spray with water should help keeping them at bay, as they don't like moist environments.