Viewing of a flat

Is there any way Openrent can contact a landlord for a viewing they haven’t turned up for?

I don’t know, but as a landlord I have around 40% of prospective tenants who don’t show up, so it goes both ways

Suggest you get the landlords contact number next time and contact them a couple of hours before you are due to view to ensure they will be there.
As stated by Graham it works both ways as we have experienced several times.
ensure you are polite to the landlord Don’t demand on the phone