Tenant threatening landlord

[Albert Johnson]

Well tenant complain of a smell in their room. We had plumber there 3 days ago and completed repairs.We was there 2 days ago. Tenant said plumber did excellent job. We did a walk through and did not smell anything 2 days ago. 

so afterthe complaint we said we could go there and inspect.

tenant started getting really angry and complaining about other things and how much rent they pay and we are greedy. Tenant threaten leave, and sue etc...

tenant also tried to refuse us entry for repairs.  We noted in the lease we have the right to entry for repairs.

at this point I stop answering. I remain professional throughout all conversations 

tenant later said that the room and closet is flooding. We think the tenant might have purposely caused damage to the unit. We are headed there to see what's going on. How do you handle these situations?