A method for detecting unwanted calls, the method comprising: receiving, at a data-processing system, a request to provide a telecommunications service to a user of a first telecommunications network, the user being a calling party, the data-processing system operated by a service provider of a second telecommunications network and the request routed through a gateway from the first telecommunications network to the data-processing system operated by the service provider of the second telecommunications network, wherein the request comprises a calling party identification that identifies the calling party and a called party identification that identifies a called party; examining, by the data-processing system operated by the service provider of the second telecommunications network, statistics saved in a database of the data-processing system, the statistics relating to all types of requests for telecommunication services including completed and non-completed requests for telecommunications services; and generating, by the data-processing system operated by the service provider of the second telecommunications network, a signal when: the called party identification in the request appears in the statistics in excess of a predetermined first number of instances within a predetermined first time interval; or a same calling party identification as in the request appears in the statistics as calling a same called party identification as in the request, in excess of a predetermined first number of instances within a first time interval. receiving, at a data-processing system, a request to provide a telecommunications service to a user of a first telecommunications network, the user being a calling party, the data-processing system operated by a service provider of a second telecommunications network and the request routed through a gateway from the first telecommunications network to the data-processing system operated by the service provider of the second telecommunications network, wherein the request comprises a calling party identification that identifies the calling party and a called party identification that identifies a called party; examining, by the data-processing system operated by the service provider of the second telecommunications network, statistics saved in a database of the data-processing system, the statistics relating to all types of requests for telecommunication services including completed and non-completed requests for telecommunications services; and generating, by the data-processing system operated by the service provider of the second telecommunications network, a signal when: the called party identification in the request appears in the statistics in excess of a predetermined first number of instances within a predetermined first time interval; or a same calling party identification as in the request appears in the statistics as calling a same called party identification as in the request, in excess of a predetermined first number of instances within a first time interval. the called party identification in the request appears in the statistics in excess of a predetermined first number of instances within a predetermined first time interval; or a same calling party identification as in the request appears in the statistics as calling a same called party identification as in the request, in excess of a predetermined first number of instances within a first time interval.