A method of providing services in a communication system, the method comprising: establishing a call instance from a caller terminal of a user to a service provider terminal of a service provider in the communication system; transmitting, via the established call instance, from the service provider terminal to the caller terminal a service proposal in the form of an electronic document, the service proposal identifying one or more services that the service provider can provide to the user; forwarding, by the caller terminal, the service proposal to a backend server for verification thereof; in response to the backend server verifying the service proposal, returning, by the backend server, a respective verification message to the caller terminal; displaying, by the caller terminal, the service proposal to the user to selectively accept or reject the service proposal; in response to an acceptance (S6a) of the service proposal, transmitting, by the caller terminal, a request for money to a backend server in the communication system transmitting, by the backend server, electronic cash tokens to the caller terminal in response to the request to receive money, said electronic cash tokens indicating that an account of the user has been debited for services identified in the service proposal, and said electronic cash tokens being embodied in a packet comprising an identifier of the user, an identifier of the service provider, an identifier of the service proposal, a monetary value, and at least one of a sequence number and a cryptographic signature; forwarding, by the caller terminal, the electronic cash tokens to the service provider terminal for verifying the receipt thereof; and in response to the verifying the receipt of the electronic cash tokens, providing, by the service provider terminal, the one or more services in accordance with the service proposal. establishing a call instance from a caller terminal of a user to a service provider terminal of a service provider in the communication system; transmitting, via the established call instance, from the service provider terminal to the caller terminal a service proposal in the form of an electronic document, the service proposal identifying one or more services that the service provider can provide to the user; forwarding, by the caller terminal, the service proposal to a backend server for verification thereof; in response to the backend server verifying the service proposal, returning, by the backend server, a respective verification message to the caller terminal; displaying, by the caller terminal, the service proposal to the user to selectively accept or reject the service proposal; in response to an acceptance (S6a) of the service proposal, transmitting, by the caller terminal, a request for money to a backend server in the communication system transmitting, by the backend server, electronic cash tokens to the caller terminal in response to the request to receive money, said electronic cash tokens indicating that an account of the user has been debited for services identified in the service proposal, and said electronic cash tokens being embodied in a packet comprising an identifier of the user, an identifier of the service provider, an identifier of the service proposal, a monetary value, and at least one of a sequence number and a cryptographic signature; forwarding, by the caller terminal, the electronic cash tokens to the service provider terminal for verifying the receipt thereof; and in response to the verifying the receipt of the electronic cash tokens, providing, by the service provider terminal, the one or more services in accordance with the service proposal.