What should I do about Tenant's inappropriate behavior?

[Rose Thompson]

I am a landlord. One of my tenants hasn't paid their monthly rent. I've contacted them many times, text, call, and in person, yet they still haven't paid the rent which includes the late fee. However, the tenant seems to ignore their responsibility to pay rent still. When I went to try to talk to them in person again, the tenant refused to open the door when I knocked (they can be seen watching tv by the window). So after I texted about wanting to go to court because of avoidance, the tenant notified me about inhabitiual conditions in the house. Which was the first time, I've heard about since months that they have moved in. So, can I envict or sue tenant for breaching the lease? The tenant accuses that the house is a "dump" infested with bugs, with no proper stove, or fire alarm (there's actually two working fire alarm when I checked last time). It has also been a week after the due date of the rent. Summary: Tenant avoids calls/texts. Doesn't pay rent nor the late fee. Tells me (the landlord) about inhabitiual conditions for the first time, after months of living in the house, when I texted them about taking the issue to court. What should or could I do?