I always return phone calls from prospective clients within 48 hours (of the days Im in the office). I think its unprofessional for them NOT to return the call as a way to 'screen out' clients. Have courtesy enough to call and say "I am not taking on new clients right now" at least. Goodness.
I've been on the other end where Ts don't return phone calls and it pisses me off. I also contacted probably 40 therapists and was open enough about having DID... That was a headache and heartache.