Charter have been reported to throttle in some areas, you *may* have better luck with some of the ports suggested in the winmx friendly ports thread.. or going way high (60,000 to 65,535 range), ultimately the answer would be a change of provider... which you say you can't do..
As to pg2 blocking your email, this is simply a case of pg2 blocking legitimate ip addresses (which it does, many thousands of them.. the pg default lists are compiled & maintained by idiots), you could make your own allow list if you want & add it, so your email wasn't blocked, however, with the winmxgroup patch, there is no need to be using pg2 anyway.