If a landlord or tenant breaches the tenancy agreement, keep relevant evidence such as messages, photographs, receipts and inspection records. Raise the issue in writing and give the other party a reasonable opportunity to put it right, unless the circumstances require urgent action. If it remains unresolved, you can apply to the RTB for dispute resolution, usually through mediation or adjudication. The RTB will decide the matter based on the individual facts and evidence; if the dispute involves ending a tenancy, the relevant notice rules should also be checked.