First off, I don't know what league you play in. And before the 'league bashers' get a hold of this thread, the league you play in doesn't make a difference, either.
And I have no idea what transpired the day/night you were banned. I'm only trying to offer a solution.
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That being said, you never know what happens with a person five minutes before you walk in. Anything's possible. It doesn't excuse his behavior, but it may help provide a real reason for your being exiled.
You know anyone that still shoots there ? All it takes is for one of them to ask the room owner, "Hey, have you seen (Al) in here lately ?"
He could say, "Yeah, geez, you know, I haven't seen (Al) in here in a while either". Sometimes a simple miscommunication or interpretation problem leads to larger unintended results. It's entirely possible that he may not realize he 'banned' you.
But if the room owner still doesn't want you in there, believe me, he's gonna tell people what happened. "Oh, I banned him because he asked someone to play on his league team."
Seriously, if it were someone else banned, and you heard that, you wouldn't want to play there either. And if he wants to stay in business, he's gonna have to accept the fact that there is a league in the area, and he'll have to 'deal with it'. I'm also sure this room owner is aware of the new poolhall (permits pending).
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If this guy wants your (and other player's) business, he'll let you back into his room. Even if he meant to toss you, he'll want you to chalk it up to misinterpretation, just to save face. You would just have to decide if you want to swallow the pill or not.
On the other hand, if he doesn't want you back at all, then spend your pool time at the new place or even the bar box place. In time, more and more players will see this guy for who he is. And they will migrate to the other rooms.
It amazes me how many business owners seem to bite the hands that feed them...