I don't understand why the need to post on a forum where this person will never see it. Just the same, you are aggravated that this person doesn't know your situation. And you're 100% correct. But with that, how can you expect them to be sympathetic to your situation if they don't know about it? Most people are reasonable; however, on the surface, all this person sees is a homeowner neglecting their property. Sounds like a little more communication would go a long way.
I won't fault the people for making a complaint assuming this wasn't an issue of your grass being tall for a week or two. Sounds like it's gone on much longer than that. And I assume you are liable to the complaint being that you're part of an HOA. If so, sorry, but that is what you signed up for.
To the points made above, there are likely very many options available to you that are economically viable. Last I checked, they don't have or enforce HOA's in trailer parks and with median home prices being in the low $300k's there, working up enough scratch for a trim every couple of weeks should be manageable. If life/situation has dictated otherwise, I am sure there are those around you would gladly help out during this rough time.
Generally, I think the response to your post would have been far different if presented differently. Hell, I live down the street from you and I would've probably offered a hand if you expressed there was a need. Now, you sound like the crazy old cat lady.