Check your tenancy agreement and report the problem to your landlord or agent in writing, describing the issue and keeping copies, photographs and receipts. Allow a reasonable time for action, unless there is an urgent danger, and continue paying rent while the matter is investigated. If nothing happens, contact your local council’s housing or environmental health team, as it may be able to inspect hazards and take enforcement action. The next step may involve a letting agent redress scheme, a housing tribunal or court, depending on where you live in the UK, so check the relevant guidance on GOV.UK or speak to a solicitor regulated by the SRA.