Confirmation letter to guest

Im encountering so much problem with guest coming in to our building unprepared. Our building require guests to submit identifications prior to giving us letter of approval for them to be a guest in our building. Security measures is very high in our building. Guests do not read booking,com messages and just show up to the address not knowing what unit they are staying. I have to call them via overseas to get a hold of them or use whatever means to get them to comply.  Non compliance means they will be denied entry to our building by conscierge. No exceptions. You are not on their list? then you are a stranger. Most of them are travellers with children since we are just located in front of the airport. They will be arriving sometimes at the wee hours of the morning and the guards and desk clerk have no way of accessing the conscierge computer. We sometimes had to meet them to let them in ourselves and its becoming troublesome because we are self check in. We live 20 minutes away from our building. This guests will call us while they are on their flight layover and they dont have access to wifi or emails. They dont answer international phone calls or text messages. We have lengthy intructions and requirements but they dont read or they have trouble seeing it in their emails, I send tons of emails and text messages just to get them to comply.  But to no avail.  Please help. They are saying they are by our conscierge but we go there and they are not there. They are lost most of the time and bother us. because they dont read. They are probably in another building or cluster. Something wrong with the messaging system of booking.com. Some guests are not getting the messages.