It is your connection that is the problem therefore you lose points, there would be no way to prove to Nintendo you didn't simply pull the cable out of the router.
It's tough luck until you get a better connection.
Personally I have the cheapest router I could find (Belkin wireless-G. £40) and it works just fine.... I have only been disconnected due to my own connection 3 times.... Once I lost about 90 points as it was early on, once I was in a team vs after one of the European GPs Ben set up, and the last time I unfortunately lost 350 points due to it... so I have had to build them back up since.








