A method for permitting a postal authority to maintain control over transactions in a franking system, the postal franking system comprising postal franking means (PFM) including a postal security device (PSD) which maintains in a secure manner funds credit data; a credit authorisation facility (CAF) and a recrediting facility (RF) for issuing a funds credit to the PSD, wherein the method comprises: (a) the CAF issuing to the RF in a limit of funds which may be credited to the PFD; (b) the PFM making to the RF a request for personal credit; and (c) the RF checking on the funds available to the PSD and providing to the PSD, if available, further credit by means of a message encrypted and/or authenticated form.