I had a similar situation some years back up here in Queensland ( tenants heaven for protection ) & it's now even worse.
Well what I did when the tenants stopped paying rent, was that I offered them a CASH for KEYS and had them out within a short period of 2 weeks.
There is one thing that a mongrel tenant loves better than free rent, & that is a wad of CASH in her/his HAND, as generally 2 factors come into play and they are either Alcohol or Drugs, & what a handful of cash gives them is availability of the one thing many of these low life's enjoy most in their lives, their Alcohol & Drugs.
CASH FOR KEYS WORKS a treat in many situations.
Now I'm ultra careful who I choose & have had no further issues with tenants.
My Golden Rule is NO Single Mum's EVER, as they are far too protected by the system.