I've played you before (even have a replay saved) I can say you aren't so bad, just need to work on a few things here and there. You can't give up if you keep losing, if it were like that, i would have quit years ago. From a fellow litchi player, you just have to understand what you can and can't do against certain characters. Like with bang, using the staff against him is dangerous, he can use his drives to block it then teleport and hit you if you aren't careful. Arakune @_@ not enough on XBL to give any real advice there, just try to keep him as pressured as possible and avoid getting cursed.
About trash talking, you can walk away from them or if they are on a mic you can always laugh at them. Gary MF Oak once said (over a mic) he hopes everyone i know dies, and hopes i get cancer and aides, i just laughed through the mic. It may be better to walk away but nothing annoys trash talkers and trolls more then seeing their trash talk being not very effective. As Kurarudo said, some high level players (i know a few of them myself) do it for shyts and giggles, anyone who does it and means to hurt someones feelings on purpose can go step in glue and wash their foot in cold water.
All and all, you can't let these things get to you, instead, save matches like those, look at what went wrong, and try to see what you could have done differently so if the same thing were to accrue later in you FG career, you have some idea of what you can do. As my friend always told me, it's all about adaptation.