Most problems with a landlord are brought to the RTB as a tenancy dispute rather than a general complaint. You can apply through the RTB’s online dispute resolution service, selecting the issue involved and providing details of the tenancy and alleged breach. Gather your agreement, rent records, messages, photographs and any notices as supporting evidence. The RTB may offer mediation or arrange adjudication, but the outcome depends on the facts and evidence; check the current process on rtb.ie or seek advice from a solicitor.