The issue isn't your ISP, or Square. The issue is actually the connection between the two. SE uses level3 for it's core provider to the internet. Their servers are physically located in Montreal Canada, and the connection Level3 uses is well to put it plainly shit. So it's nothing either side can do. The real core main source of the problem. Square picking a horrible city to host all of it's NA/JP servers. Instead of like Los Angeles where one of the core internet hubs is and several dozen mega clusters and practically everyone hosts out of. Nobody uses Montreal except for it's Canadian server, like steam for example uses it but also uses LA, Chicago, Philly, Dallas other known mega centers for internet traffic.