A kitchen that didn't even cost 4000€ and is even called junk by (mother) herself will hardly bring in anything with normal common sense.
On the other hand, one can also argue: after 3 months, minus 20% paid... now 11 years have passed... basically, you still have to add money.
How it can be done: explain to the landlord that you leave the kitchen in for a small fee. The landlord will be suspicious anyway, because he assumes that. Anyway: he should ask the next tenant how much they would give, otherwise it goes out.