If you cannot resolve the issue directly, either the tenant or landlord can apply to the Residential Tenancies Board (RTB) for dispute resolution. The RTB may offer mediation or refer the case to an adjudicator, who will consider evidence such as the tenancy agreement, photographs, inspection records, rent statements and messages. The adjudicator can make a legally binding determination based on the individual facts, including whether any deduction from the deposit was justified. Check the RTB’s current application guidance and deadlines, and consider getting advice from a qualified solicitor or tenant-support service if the dispute is complex.