Method for allowing a cash adjustment between payment systems in communications network

A method for allowing a cash adjustment, relating to a purchase transaction, between a first payment system in a first communication network and a second payment system, the first payment system having an associated purchaser and the second payment system having an associated vendor, comprising:

• charging the purchaser a sum of money which is dependent on the purchase message, upon arrival of a purchase message relating to the purchaser in the first payment system;
• producing a first data record which relates to the purchase transaction, the first data record having a structure corresponding to data records used for billing in telecommunication connections;
• transmitting an acknowledgement message relating to the charge to the second payment system;
• crediting a vendor account associated with the vendor;
• and
• transmitting the first data record to a billing center, to bill for telecommunication services between telecommunication networks, and to allow the billing center to make a subsequent cash adjustment between the first payment system and the second payment system.