Appointments for Showings

Yesterday I took a client to see two properties listed for sale.  One appointment was made through the listing broker and I was told there were multiple offers but I still could see it.  The second appt was made through an appointment making company.  I usually love making appts this way because they always answer the phone and I know right away if I can see the house at the time I want.  This time, however, I made the appt and we saw the house and my Buyer wanted to make an offer so I called the agent when I got back to the office and the agent said the house was not available as an offer had just been accepted.  I always try to learn a lesson when something doesn't go right.  My lesson here was I will have to call the appt making company for the appt AND I will call the listing agent to get details.  It was a huge disappointment for my buyer as we thought it was still available.