Internet/ping question

Hi Everyone, I've been playing league for 4 years now, and I've been through it all when it comes to lag and ping spikes and have always been able to figure out what the problem is and solve it myself. However, I've recently moved to a new state with new internet (Grande Communications), and I have been having a lot of trouble with the ping. Most days, it's completely fine and doesn't bother me, but other days it's just awful and unplayable. The bad days can either consist of a consistent ping of ~150 or spikes up to 500 for about 3 to 5 seconds. It's incredibly frustrating, and after a long day at work, being prevented from enjoying a game of LoL is just unfair. I have tried using a gigabit switch, plugging directly into my modem, contacting league customer support, contacting grande customer support, and nothing has helped me. I use an ethernet cable.

Here are examples of a good day, a high ping day, and a ping spiking day:

http://logsoflag.com/#480M6Lf1-VS http://logsoflag.com/#480M6Lf1-VS http://logsoflag.com/#s475-jdcfPj

Any help would be greatly appreciated. I'd love to be able to depend on my game running smoothly after coming home from a 14 hour work day.