Slow Connection to certain Sites

Hi Everyone,

I'm running into a problem that is driving me up the wall. When accessing certain platforms, such as Microsoft or AWS cloud platforms, i get insanely slow speeds, like 600kbps, on large files, but if i try and download the same file from google i will get closer to 25 to 30 MBps, which is basically the 250Mbps speed i pay for. I see similar download speeds on steam and have checked my speed via cloudfare, speedtest, fast and all say i'm getting what i expect. I have called my ISP and they claim theres nothing they could be doing that can cause that. I have repeated this experiment on my home laptop, work laptop, wifes laptop, all both either plugged in via ethernet on a dock or on wifi and am able to reproduce this issue every time.

I tried replacing the router and that was unsurprisingly not the issue.

For history, i spent 10years with an internet Reseller called Tek-Savvy which ran on the canadian ISP Shaw (now rogers) and recently switched to Lightspeed (also Shaw), and that definitely seems to be the source of my issue, but i cannot for the life of me figure out why and the lightspeed guys insist it can't be them issue.

Any insite you guys might have would be fantastic.