If they are not that busy a venue, or the SP lives near by, Polish Sergei in my experience will often call the SP to come to the flat for an appointment - if you where the first appointment of the day, this is more likely.
I suspect she was running late or was not available for work that day, Sergei didn't have confirmation she was working that day but Sergei goes ahead and takes your booking, working on the chance you would come and the SP would confirm she was available after you where on your way.
Assuming it was Sergei's fault, its a shame because its burns bridges with customers at both the working flat and with the SP, as you will be weary of both now IMO.
