Intermitent Signal drop

Since it started getting cold in roughly october, I have had periods where in the evening the signal will drop  to nothing or very very poor quality for minutes at a time. This usually lasts 2-5 hours for a random number of days, and eventually clears up for a while before coming back a month or so later.  

When I call the help desk, they just want me to reset everything (which never helps) and then they want to send someone out to check the lines. The same tech that did my install came to check my lines, and said everything looks brand new, and that I should call to have someone check the lines in the area.

 I thought this sounded pretty straight forward, as the end of 2012 and beginning of 2013 there were some bad storms in the area.  Since then, I haven't had too much trouble except for a couple outages, which when I called and inquired about the lines being checked, the customer support informed me they couldn't help me because they could not find my modem (outage, duh) and therefore could not look at any information about my past work history, which I found odd.  

I called tonight and fought through the same turn off/on and we'll send a guy out lines, and insisted on talking to someone that could help find out if anyone had looked into the lines in the area.  The lady was extremely unhelpful, but not rude, and transferred me to a proffesional tech support PREMIUM service, that would charge me for help with my in-home equipment tech support. Completely not what I need help with.  

Please help me understand why this issue is so difficult for the tech support line to deal with, and also try to help me resolve this.  Streaming movies is no big deal, but playing games online, or other content which cannot be buffered, becomes untenable with this issue.

Thank you