彼らは私を不当に扱った。

they (usually male); them

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

I; me; private affairs; personal matter; secrecy; selfishness

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

injustice; impropriety; unreasonableness; undeserved; unfair; invalid

at (place, time); in; on; during; to (direction, state); toward; into; for (purpose); because of (reason); for; with; by; from; as (i.e. in the role of); per; in; for; a (e.g. "once a month"); and; in addition to; if; although

to deal with (a person); to treat; to handle; to take care of; to entertain; to deal with (a problem); to handle; to manage; to operate (e.g. a machine); to handle; to work; to deal in; to sell; to cover (a topic); to treat; to discuss; to take up; to treat A as B; to mediate (an argument); to be too much for one; to find unmanageable; to gossip