Typical consumer's interpretation of a 'slow' connection issue. It's usually not a localized issue (though it's possible), TM's practice is to perform initial troubleshooting at your end for possible hardware issue. But given the pattern that you said (bad ping at night), then it's possible that its due to a congestion within your area so the issue is most likely within their exchange.

Won't be solved until they perform an upgrade within their exchange. Or they do a better job of load balancing.