Define "harassing." The entire range of criminal and civil law protections is at your disposal, the same as would be with any other neighbor/neighbor dispute.
There's really not much a landlord can do about this. You need to handle this case as if it were anyone harassing you. Either get a restraining order or call the cops.
You cannot stop the repo company from harassing you unless you pay your bill. The only thing you can do is try to ignore them.
tell her
get a restraning order against them
tel him to please stop or tell your parents.
Throw a cod fish at them
He can stop and interact with you if he is investigating an unusual occurrence. "Harassing" has no meaning.
Pay her back of course.
i don't know! stop harassing me!
Get a police order of protection
You need to contact your attorney about having them stop. There is no law unless you have declared bankruptcy that they have to stop.
tell them stop you are hurting me. i am crying inside. i don't like when you hurt me. please, i am scared by your harassing, sometimes i cry in the night. or tell their mom or try to write a letter to gov. shwaarzenegger