Unused minutes were rarely usable on a second call.
The provider provided (say) 10 minutes of service, but got to keep all of the money (say 20 minutes).
Human dispatchers — female, except for gay male phone sex — answered the advertised phone numbers, processed payment via credit card, chose who of the available performers in the dispatcher's judgment best matched the clients' fantasy (grandma, black girl, college girl, etc.), and connected the client with the provider. Either could hang up, though some services put economic pressure on providers not to do so.
Originally, per-minute billing was provided by phone companies (in the U. There was, from some services, an attempt to keep the caller aroused but short of orgasm, so he would spend more money.
Leonard herself was surprised at the success of these numbers.