I am currently a tenant at their apartment in Rich...

I am currently a tenant at their apartment in Richmond ,VA Brookside. I have always paid my rent on time so when I received a notice of material non compliance I was confused as to why I would get this for Octobers rent when I paid that on 10/4/2017 by certified funds/ money order. Today I went to the office at Brookside to get answers as to what is going on with my accounts and was threatened