It never ceases to amaze me the self entitled attitude people have when its they who made the mistake.
it is not the landowner who didnt return your items, its the computer program that is Second Life, All the land owner can do is click 'return obkects owned by others' on the About Land. Itis the Second Life program that is responsible for the items finding their way backto you. Try sueing Linden Labs. The cost to file the suit is more than your items are worth.
If the landlord repossed the land for non payment, did you pay them what you owed for back rent? If not, how come? They kept their end of the agreement when it seems you didn't keep your end. I think they would have the stronger case.
Do you REALLY think a land owner would/should/is going to leave someones items on a parcel waiting for them to be picked up? Many people just leave SL and never return. It's standard operating procedure to hit 'return' when tkaing back land. There is no 'knowingly causing loss'. If you defaulted on the agreement, then they need to rerent that parcel and recover some of thelosses that YOU caused them. If you couldnt keep up on your rent to the point that the land was reclaimed, thats your fault for not removing the items yourself intime, as is any losses resulting.