Most likely they are doing updates in your area. This happened around me for a week or so. I just happened to be in an office next to a staging area for their trucks, at the same time I was having problems, they had about 100 trucks and tons of workers in the area. If you call them, they will most likely give you some money back, but they will not admit that they are doing line work - that would be too difficult for some reason.
It will not be a problem for long. But annoying that they never contact their current customers to notify them of network upgrades. On the plus side, after the upgrades, I have seen some downloads in the 20+Mb range and uploads of around 5Mb.