Ask the landlord to explain the increase and check whether the notice follows the current rent-increase rules, including any applicable Rent Pressure Zone limits and notice requirements. Compare the proposed rent with similar local properties, but remember that a high increase is not automatically unlawful. Do not simply stop paying rent; instead, keep records and consider contacting the RTB or using its dispute resolution process if you believe the increase is invalid. The outcome will depend on the tenancy’s dates, location and individual facts, so consider legal advice for a complex case.