Sounds like you're getting routed through some congested/bad hops when going to FFXIV services. If you can, try using a free trial of a VPN like WTFast while playing to see if your issues clear up. If so, you can either invest in a VPN or ask Cox to find a better route (you'll have to be really, really persistent with the second option though- and there's no guarantee they'll actually do it for you).