You should verify first that it's not your own wiring that's causing a problem. If that's the case then you would just be taking your issues from one ISP to another.
If you have a master socket spilt in two halves then plug into the test socket behind the faceplate. If you see an improvement then your filters and/or internal wiring are at fault. Here's a clip on Youtube that shows how to do it . If that gets deleted the go to youtube and search videos for master test socket.
Only consider the actual connection rate between your router/modem and the exchange, download speeds are a different issue. You should get your line stats from your router/modem to chaeck downstream snr margin, sync rate and attenuation(line length). Would post a link to a helpfull site but it just gets deleted. Google line stats and kitz and you might get there. Kitz is an engineer who knows her stuff.