Intermittent Connectivity Drops

Ever since I had my original line installed, and with the previous company I had as well, the router that I'm using will stop working for 5-10 seconds at a time every 5-20 minutes. I've had sleuths of techs come out, at least 50, all showing up, checking the wires, finding no problems and leaving with shrugged shoulders. as someone who uses the internet as their job, one that needs a constant un-interrupted flow, this is obviously quite annoying. What can be done?