Here are some ideas that we have used with clients which can't be on 24/7:
Communicate Clearly: Be sure to clearly communicate when you are or are not available to provide customer service to exsisting customers. Make a clear communiicate to prospective customers of how long they should wait to hear back from you if they are leaving a request for additional information. for example: T"Thank you for contacting us. You will hear back within X hours."
Use all means at your desponsal to communicate accessibility: Phone, email, online forms, live chat, twitters, instant messenger, Facebook Fan page. Your unavailability sometimes will be offset by the message of accessibility which you communicate.
Leverage Live Chat features. One geeat option to expand your coverage is to integrate live chat into your site. Many providers (like LiveChat) have clients for your smart phone or tablet to expand the times your are available. A quality providers platform will automatically show aviaabiliity so people aren't engaging chat with someone who is not there.
Integrate your responders: You can have a response from the phone, the email, and the LiveChat, instant messengers -- make sure that they are all integrated effectively with your CRM so that people get quick responses that are within the context of their relationship with you.
Use a PDX Service: Whether virtual or not -- be sure to really use the capacities of your voice mail. Be sure to post time-relevant messages. if they are reaching you during posted business hours -- then acknowledge that you are with a customer and will back to them shortly. If they are contacting you during non-posted hours, acknowledged that and get back as soon as you can.
VM to Txt/email: Sending your voice mail to your email or text message allows you to more effectively triage your response during your limited availability windows (walking between class).
Use Phone Answering Services: People love a live person to answer the phone. From phone answering services to virtual assistants -- the relatively low cost of having a live person pick up the phone is invaluable. Most of these services you pay by the minute used. Be sure that they are effectively integrated into your CRM so that you can maintain a high level of customer service across your communications platforms.