You may have to serve the tenant with the legal notice of early termination for non-payment of rent which is the Form N4, do no include utility charges on this notice. You can serve the notice by hand, but if that's not possible the notice can usually be slipped under the door, placed in the mailbox or where mail is ordinarily delivered or it can be sent by regular mail (if sending by mail add 5 days for mailing time). Once the tenant receives the notice they will have fourteen days to pay the arrears of rent. If they do not pay, you can file an application with the Landlord and Tenant Board for early termination of the tenancy. For forms visit- https://tribunalsontario.ca/ltb/forms/#landlord-forms.
As of September 1, 2021, landlords can file an application for failure to pay utility costs with the LTB.  For more information on the September 1 amendments to the Residential Tenancies Act visit https://tribunalsontario.ca/ltb/operational-updates/#sept1.