I know that in order to clean the surface affected by the fungus, you need to use special disinfectants. But in practice, this does not always work effectively. Therefore, I advise you to understand the reasons. You may have poor ventilation or there is somewhere a leak in the hydraulic system. For example, we had a problem with waterproofing. Therefore, the husband found a company that provides interior waterproofing services and called a specialist. After we had a waterproofing, the walls became dry and the problems with mold solved.