honesty, professionalism
I prefer someone who is honest, professional, and courteous in their manner / speech. Especially if they are going to be working for me...I don't think you are being rude or unprofessional - be honest and move on. I would however, mail them a thank you note in writing immediately following your visit. Then when they call - you can explain the situation and instead of 'get back shortly' give them a date / time - it will look much better than the ambiguity of 'shortly'....
My two cents worth...
-LA