Set Max connection speed for firefox?

[Zyrtantar]

I have a little problem with my Firefox; my ISP cuts me off if I reach certain connection speeds and firefox reaches those speeds. I have to do everything to avoid this because the cut off is for 10 minutes usually and it ruins my downloading. How do I set the maximum amount of running downloads for the default downloads for the download manager and set the maximum connection speed for firefox downloads and overall browsing?

Any help is appreciated

[Lsdmeasap]

Netlimiter