This is a public forum so don't post your private info here. However, if Tim_k asks you to pm him your info, that's ok to do so since he works for Verizon and he can look remotely at your line.
You can post your problem on Verizon Direct: »
Verizon Direct but they're only around on weekdays during set hours. The guidelines for posting there are here: »
Posting Rules - They can follow up with you after your tech visit to see if things are fixed.
Generally, declines in broadband come from problems on your line (like excess noise) or from too much traffic at your DSLAM or other circuits. If your slowdowns come regularly at a set time such as weekdays after 5pm, it's likely you have a traffic problem. If you have phone service with your dsl, you can check for a noise problem by lifting up a phone receiver and pressing one button and listening for any static.
You might be able to find some useful stats telling you the condition of your line by opening a browser and typing 192.168.1.1 into the address bar, which should open a page to your modem. If your modem gives SNR, attenuation, download/upload speed stats, those things are helpful in diagnosing a problem and are ok to post here. Don't post MAC addresses and IP info, though.