If they were doing a bust, they must show you prove that they are cops. I have never heard of this. Maybe they were just crackhead punks looking to sell the weed they stole, as everyone knows that true pot heads are noble citizens who dont steal. I'm sure they werent cops if they didnt call you back about this.

But try not doing these transactions in public. Do them at a house or something in private. Thats lowers your risk a lot!