And you always want to keep the lines of communication open with employers. So even if you don’t hear back from someone, a follow up never hurts as long as there’s been a decent amount of time given. Next day follow ups are verging on stalking. Just give a week or two and then reach out again. Friendly reminder that you’re around, etc.
Whether intentionally or unintentionally, never make more out of an unreturned than just that. A missed call. Move on and maybe follow up down the line.