A method and system for operating a telephony service are disclosed, in which callers with insufficient credit or network airtime are able to contact a call recipient. The network monitors call attempts from callers to identify call attempts from callers with insufficient credit or airtime to make a call. When such a call attempt is detected, a call request is transmitted to the intended recipient of the call, to notify the recipient of the call attempt. The notification may take the form of an in-call notification if the call recipient is on-line, or an SMS or voicemail message if the recipient is off-line. The method and system permit individuals who otherwise would not be able to access the network to indicate to a call recipient that they have attempted to contact the call recipient. The call recipient can then contact the would be caller at his/her discretion.