The more you say, the more it's clear that something is going on.
Or more possibly, a couple of different things going on which are separate but all contributing to your awful experiences and this terrible harassment 
A couple of times in my life, I've ended up in situations where I was being abused, and suffering terribly. One was my childhood and one was my marriage.
When I tried to tell people, my distress and the way it all came tumbling out, the really bad stuff and the little things all mixed together, well... it made people react in unhelpful ways that remind me ALOT of your situation.
It's really hurtful when people dismiss you. And I know your situation is different being about harassment not abuse, but I stayed in abusive situations longer as I couldn't somehow get anyone to acknowledge my situation and it stopped me from taking action and getting help. I felt powerless and isolated and utterly miserable.
To me, the little things and the big things were as upsetting and damaging as each other. And I couldn't separate it all up. It's hard when you're living it.
But eventually I did learn from it although a huge bit of me thinks I shouldn't have had to learn! But, sadly, reality is that people don't react well and rather than keeping on getting that reaction (which I found almost as distressing than the actual abusive situation I was in), I had to change the way I was telling people rather than hoping they'd change and be hurt each time they didn't...
This is what I did, I'm sharing in case you find it helpful, I'm quite practical and I can hear such pain in your voice and want to help you the best way I can
- Write it down, and get it all in one place, don't share it yet, this is the most personal stuff. It's a huge mental download of every single thing that's happened and how it's effected you. Keep this version to refer to but now use it as a base for editing:
- make each event/ occurrence into bullet points
- put it in order and add dates and times for everything. Take out anything that doesn't have a date next to it (that prunes out any general statements)
- make sure each bullet point starts with what happened, and Not with 'how it effected you' or a general 'label for that type of behaviour'. Let the events speak for themselves.
- then go back and delete any emotional words (to make sure people 'hear' the facts and not just react to your emotion)
- then go through and add more facts, more detail. And keep taking out general statements.
- and after all that bloody hard work 😓, I'd go through and star the 'biggest' events that seem most clearly stalking or harassment. And next time you try and get help, try starting with these points and using factual sentences first, so you're making it easier for people to 'hear' what's happening...
You may have to do this in short sessions as it's hard work and upsetting remembering it all again. I wrote bits and added to it over a few days. The editing is really hard as you have to almost take YOU out of the text, which feels weird & is difficult to disassociate your own overwhelming feelings from it.
But it's really worth it. I'm saying that as someone who went through it herself. No preaching or judgement here 
Facts work loads better than general stuff. Lots of emotive describing words seem to just get heard as your opinion and value judgements, rather than specific and factual events.
If you manage to do all that, I suspect you'll naturally start using language and phrases that reach people's brains without getting diverted down a blind alley!
When you've got this summary of what's been happening, with stars against the 'biggest' things where it's not up for debate that something definitely happened... then you can also look for patterns 👀
More on patterns later if you can bear reading any more from me!
