RaikuFA said:
1. cannot connect to any servers. "there are 250 servers that match your criteria. unfortunately, none of them want you"
2. if i do get connected, i get booted about 2 to 3 minutes in because im not "teh hardcore" despite the fact that ive played for about 20 hours or i get dogpiled by the enemy
3. ive never won a game i stayed in, and guess who the blame goes to?
4. spy=cheater. seriously, ive been up against the wall and i get backstabbed. and when i try to disguise myself and backstab? knife never goes up to imply that i can backstab when im RIGHT ON THEIR BACK!!! then i get killed
and dont even put up that "it gets better" poster, cause it dosent
Sorry to rain on your parade, but most people in TF2 (at least the servers I play on) say it takes roughly 100 hours of play time on one character to understand the basics, and when I casually mention my 250+ hours on scout I still hear people tell me how I can do things better.
With only 20 hours you are, by definition, a noob to most of the player base. But keep in mind, this game has been out for years, and most people who play (at least play it well) have stockpiled many countless hours into it. These are the people you will have to contend with, and it's not easy.
Now, player skill aside, you may have issues with ping, I personally won't play a server with 80+ latency.
Find a server you have good connection to, repeatedly play on that server or other servers affiliated with it, get to know the admins and usual crowd of players, and ask for tips. Never, ever, ever be a jackass, especially if you're new, and sometimes you'll have to bite the bullet and deal with jackass admins and usual players. You'll learn the game through experience, but after only 20 hours of gameplay you probably don't really know how to deal with every situation.
TL;DR: This isn't Call of Duty or Halo, 20 hours of gameplay means nothing.