Not related to League; constant 600 ping

I have no other place to post this and I highly doubt you guys can even help me, but fuck it right?

Long story short, I use time warner cable and for the past week I've been constantly getting 600 ping. I really want to play/enjoy Urf but this completely ruins the experience for me. There's no point in calling my ISP because all they're going to say is "it's your fault, we're perfect, gtfo". I don't use WTFast because last time I tried it, League would crash every time I tried to start a match (and when it did work, just made my lag even worse). Is there something, anything, I could do to fix this, or am I not going to be able to play Urf this month, and just deal with the fact that my ISP is shit?

Also, did a pingtest while writing this, apparently it's 58 with 27 jitter, which is bullshit because if I start a game right now it'll be over 500.