If your agents are Offline or Unavailable when a new lead comes in, Callingly has the ability to send an SMS message to your lead letting them know that you will be in touch shortly.
This feature is enabled per-team on the Teams page, simply click Edit on a Team and scroll down to Send SMS If Team Offline Or Unavailable. You can turn that feature on and then include a message that you would like to be sent.
In order to enable this feature you will need to have a purchased Number on the Caller IDs page. The text message will be sent from this number and if the Lead responds back, their message will be forwarded as an SMS to your agents (the ones assigned to that Caller ID number) so that they can then respond directly.