I don't believe them. I am almost back to normal speed now. I think it was that heavy rain we had yesterday. I also changed my DNS servers and made a good difference.
Every once in a while my internet speed slowed WAY down. And when I say WAY down, specifically 0.01mb/s instead of @13mb/s. Quite often I noticed it when it rained so they sent out a tech to take a look. There is a cable splitter outside where the line meets the side of our house. When he unfastened the cable splitter, water spilled out of it.
They finally installed an outside box to protect where the line gets coupled by the cable splitter. It sounds like either a cable splitter is getting wet or the outside line might be going bad. Our outside line was replaced years ago, too, because of the problems it caused with cable TV--the picture was snowy, etc.