Même en allant sur la carte comme tu l'as fait, en sélectionnant ton immeuble au 7 rue de l'étang et en suivant la procédure d'abonnement ça ne fonctionne pas ?
Parce que même si les deux immeubles portent bien la même adresse, même dans la base Free ils sont bien physiquement différents : localisation différente, identifiant immeuble différent, PM différent, etc.
Ton immeuble dans la base Free :
{
  "cf": "extern",
  "gid": "1580235962",
  "srs": "EPSG:3857",
  "x_lng": "55391.8402758339",
  "y_lat": "6334864.93522005",
  "wgs_x_lng": "0.497593367352883",
  "wgs_y_lat": "49.3523749242557",
  "building_id": "IMB-27467-AAAQQ",
  "building_status": "DEPLOYE",
  "pm_reference": "PMU-27-242-00F",
  "pm_deployment_status": "ELIGIBLE",
  "address_id": "8074174",
  "address_src_id": "27467223SR",
  "street_nb": "7",
  "street_suffix": "",
  "street_type": "RUE DE L",
  "street_name": "ETANG",
  "postal_code": "27500",
  "insee_code": "27467",
  "city": "PONT AUDEMER",
  "department_code": "27",
  "department": "EURE",
  "building_type": "IMMEUBLE",
  "building_info": "",
  "fiber_status": "ELIGIBLE",
  "fiber_eligibility": "1",
  "fiber_freeze": "NONE"
}
L'immeuble à 500m dans la base Free :
{
  "cf": "extern",
  "gid": "1580235016",
  "srs": "EPSG:3857",
  "x_lng": "56009.2885592677",
  "y_lat": "6335887.79503844",
  "wgs_x_lng": "0.503139999654518",
  "wgs_y_lat": "49.3583599999261",
  "building_id": "IMB-27467-AAERH",
  "building_status": "DEPLOYE",
  "pm_reference": "PMU-27-242-00E",
  "pm_deployment_status": "ELIGIBLE",
  "address_id": "8074174",
  "address_src_id": "27467223SR",
  "street_nb": "7",
  "street_suffix": "",
  "street_type": "RUE DE L",
  "street_name": "ETANG",
  "postal_code": "27500",
  "insee_code": "27467",
  "city": "PONT AUDEMER",
  "department_code": "27",
  "department": "EURE",
  "building_type": "IMMEUBLE",
  "building_info": "NA2",
  "fiber_status": "ELIGIBLE",
  "fiber_eligibility": "1",
  "fiber_freeze": "NONE"
}