Joomla component to import users to AEC

Job description: I need a Joomla component that imports users from an Excel document and adds them to a certain AEC* Payment Plan. (*AEC=component for Automatic Expiration Control, [login to view URL];task=view&id=17&Itemid=34) The list will be imported every day, and every time the list is imported, all the existing users in that AEC Payment Plan must be automatically deleted prior to importing. The Excel file will have only this information about the users: Column 1 contains [Firstname Lastname] and should be imported as username. Column 2 contains customer number and should be imported as password. There is no email address to import. Please inform me if Joomla has to be hacked because of this, if it is more than one file, and if it has security implications. Explanation of the function needed: We have an external database of clients without email addresses. These clients subscibe to another (offliene) service for different time periods. We want to give these clients access to download documents from Joomla/DocMan during the timespan of their offline subscription. The offline database exports two different Excel files daily: 1. A list with the actual subscribers active today. 2. An in/out list, i.e. a list that tells who is a new subscriber and whos subscription expires today. My first thought was to use the in/out list to change the list of actual subscribers every day. But I figure that if connection would be lost during an update, it could cause some problems when retrying to delete a subsciber that was already deleted. So I guess it's easier to delete every user and import every user again every day. So list 1 is the one to use for this. Only negative is that this list takes more time to import since it has about 8000-9000 subscribers. Note that not all Joomla users should be affected - not even all AEC users, but only the users for a specific AEC Payment Plan which is set to give all its users access without expiration (the expiration is ruled by whether the offline subscription manager puts them on todays list or not). If you didn't get the idea, please read it again ;) If still not clear, please write me a PM. You are welcome to suggest alternative solutions if you think yours is better than the above.