A verbal agreement can still create a legally recognised tenancy, and if the arrangement is covered by the Residential Tenancies Act, tenant protections generally do not depend on having a signed written contract. A written agreement is useful because it records the rent, deposit, responsibilities and notice arrangements, but emails, messages, bank payments and witness evidence may also help show what was agreed. Ask the landlord to confirm the key terms in writing and check whether the tenancy has been registered with the RTB. The RTB or a solicitor would assess any dispute based on the individual facts.