Anedgena Adamski

Please explain to me why my lindens are disappearing from my account....they disappear 1 linden at a time....I had 1000Lindens in my account....I log in a week or so later and i see i only have 999 Lindens...I log in today and I see only 998 Lidens?! please explain why and how this is happening to my account?! thanks