Wow, you are making a lot of assumptions here, and ( from one technical professional to another ) made a technical mistake of confusing CloudFRONT, which is the decentralized server infrastructure by Amazon, with CloudFLARE, which is what I said we use, that is an entirely different service offered by a different company.
You are not downloading anything from Amazon S3 directly. You are not downloading anything from Amazon at all, your downloads are only happening through Cloudflare, which is a totally different service, that acts as a cache for all downloads, not conceptually different than Cloudfront, but not the same service and not the same configuration.
We can control what is cached by Cloudflare, and we can force a cache refresh for some files, but not much else. We don't have any control over individual nodes, or how they are assigned to end users.
Your other assumption is that, when I reply "it's not me", is done automatically before testing. That's not the case, whenever a user reports a problem, I always verify it personally BEFORE replying.
To test problems with their local connections, I use a commercial VPN software so I can test AS IF I was located elsewhere, and that's my usual routine when somebody reports a download issue. Only AFTER testing this way, I can safely say for sure the problem is local to the user. Perhaps it's a routing problem caused by their ISP. That's why I pay for a yearly subscription for that VPN, ONLY to put myself in user's shoes, so to say...
This happened TO ME, as a customer, several times. There are some servers which I know they are perfectly fine ( because I HAVE tested them with a VPN ), which become VERY SLOW if I access using my local Cable ISP. I troubleshoot that to be a routing issue, since the packet takes a very strange route and pass through places in which many packets are lost, while if I use a VPN, it's way faster and no packets are lots.
Of course, as a user, I don't go complaining to the owner of that site I cannot reach, saying "are you sure it's not you ?" because, before complain, I tested with a VPN, so I was sure the remote site was "innocent", and the problem was my own local ISP routing.