Dehumidifier (Coxheath ME17)

I have recently moved out with my daughter and the flat I have started renting is suffering serious damp with mould growing over the walls window and roof after only 10 days of living here I have been told a dehumidifier may help I do have the vents open and windows ajar but nothing is helping is not affecting the clothes in the wardrobe with them all being damp I’d be very grateful if anyone has a dehumidifier they no longer need

Thank you in advance