Generally speaking, complaints are settled directly with retailers. But it does happen that customer and retailer do not manage to reach agreement: that is where the Ombudsman comes in.
The Ombudsman for Retail intends to reconcile customers and retailers. The Ombudsman for Retail is only competent for registered retailers. The conciliation procedure takes place online. An independent conciliator analyses the case and expresses a neutral opinion. If the customer and the retailer concur with that opinion, the conflict is settled.