If they own the property and you do not have a lease, or if they are contracted the property owner and there is no lease, then they may have that right. However if you have a lease for that property, than no.
If you don't have a lease, then it is considered to be a 30 day or "month to month" lease. There are different laws in each state about how a landlord can remove you. You can google "landlord-tenant laws for ___(your state), and it should come up and you can read thru it to see what rights you have and what rights he has. IN most states, they first have to post a "5 Day Pay or Quit" notice and it must say what grounds they have against you,and you have 5 days to correct the offense. If you haven't paid your rent, then you have 5 days to pay it or get out. If you don't pay, after the 5 days (and you aren't out) they can go to small claims court and get you evicted. Your landlord may not know the state law because I can't think of any circumstance where he could lock you out without getting awarded an eviction from court.
Read your lease. Assignments, agents, and such may well do just that. Go see a lawyer, quick, many fail to follow the letter of the law, and you may get a reprieve, and maybe even damages awarded. Good luck.