I am sorry to hear this too. You can perhaps imagine how many enquiries we take - which isn't to excuse a failure to call back, I hasten to add.
I would observe though that we often find that not all enquirers have ansaphones, nor do they leave their mobile phone numbers. We make best efforts to call back, but after a couple of unsuccessful attempts we have to move on.
Enquirers are also always welcome to follow up with me directly - it isn't as if I am invisible, after all ... ;)