I will suggest you read your Tenancy Agreement to find out whether there is any clause regarding Tenant's default, and what can the Landlord do in the event that the Tenant fails to pay the rental promptly.

But usually, the process is letter of demand (to settle outstanding) > termination letter (request to move out) > police report > find a lawyer to file court suit

You may find a police or a lawyer to assist you in this situation, but u cant terminate the water/electricity, or lock the tenant in or out, it is illegal.

Is there any Tenancy Agreement? Read the Tenancy Agreement first, to find out are there any terms protect you as a Landlord.

You can send a Letter of Demand to the Tenant to their correspondence address stated in the Tenancy Agreement - demand your rental and take legal proceeding against them if they fail to do so.