I suppose some blame could be put on the receptionist for not making it clear you had to be ready for 12.20 on the dot......or maybe she did? However the other staff member probably didn't know you were having a shower and after seeing you hadn't arrived on time gave your appointment to someone else.....which I think is fair.
You really should have thought of taking a shower a bit earlier or having one after the appointment. To call it bad service is a bit OTT.