So this only happens every 7 days?
Is this your internet connection or are you connecting to someone elses?
There is a hotel chain that issues free internet in 7-day blocks to which you need to revisit their home page and request another 7 days of free lower speed internet with option to paying for faster bandwidth, which comes to mind. As I have run into the 7 day lease connecting to hotel networks. So this has me thinking that maybe your connected to someone elses network that gives out 7-day leases on internet.