Ping Issue?

So, I've been having in game issues and it has done nothing but frustrate me. Even with the servers being moved I would get around 70-80 ping. Lately within the last couple of months, I have been having issues in game where my ping with shoot up to 120-200+ causing me to break combos with champs, lose ground chasing or running from others. I've done about everything I can do on my end such as resetting modem, closing all other background programs, and even repairing my client many times. Still not fix. Some nights my ping does not fluctuate as much and others it is a nightmare. I feel like it is a handicap in the game and I'm frustrated with it. My provider is Cox, does Riot not have a great connection with them?