Why Linden Lab ask me payment of land fee now if I don't have land?

[stufso]

I have sold the most part of my mainland parcel and the reaminder I have abandoned during October's month; Why now Linden Lab ask me payment of land fee if I dont have land???

[Rolig Loon]

Because if you owned any land for even one second during the billing period, you owe land fees for the entire period.  The Land Use Fee is a monthly charge for the peak amount of land held during the previous 30 days, including actual parcels held and land tier donated to groups.  The best time to sell or abandon land is right at the end of your billing period.  Since your land fees pay for the whole period, you might as well use the land for as much of the time as you can before you get rid of it.