Yes, a landlord or tenant may apply to the RTB where the other party appears to have breached the tenancy agreement or their legal obligations. First, try to resolve the issue in writing and keep relevant evidence, such as the lease, messages, photographs, rent records and repair reports. The RTB may offer mediation or adjudication, and any remedy depends on the facts and evidence; it is not guaranteed. Check the RTB’s current application deadlines and procedures, and consider speaking to a solicitor if the dispute is complex or involves a threatened termination.