I'm very sorry to hear that you're upset about what happened. I remember reading that you've been having complaints for awhile. I think we all make mistakes like that, and of course feel like the worst people in the world.
If you just sent that email today, I'm sure the landlords will see it soon (hopefully today) and see your correction. If they were that quick to respond to the compliant, they surely are around to see their emails. I'd imagine they didn't get very many emails either, so I don't think it would be lost.
If they don't apologize for the mistake, then maybe you can apologize to the man? I get that can be hard to do, and sound very anxiety inducing. It would be hard for me too. I'm not someone who can be that able to admit a mistake and hope for a good response, I'm someone who always expects the bad outcome. I'm sure that if he's as nice as you say, he can realize it's a mistake and something to laugh about later. Or maybe write a letter?
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dear god, dear god, tinkle tinkle hoy.
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believe in the broken clock and who's side will time be on?