I do not smoke pot but being accused of doing so, what do I do?

UK BRIT- fighting this may be hard and if you don't feel like it then move. But I do have some advice for you if you do want to fight. Get yourself a solicitor (lawyer) and make a suggestion that you do a drug test, drugs would show up in your bloods! Number two if your building manger says you've been smoking drugs months ago then you can give the police a hair sample, all drugs show up on hair even if you smoked it months ago and as you haven't smoked anything you win. These people are bullies and you may have to face up to the fact that if you fight then you may be bullied for as long as you live there. Is that worth it? Good luck though.