Each of these is a refusal this regime lets a counterparty attempt, paired with the answer to it. Reading them before you write is worth more than any amount of polish on the letter itself.
"That money was reikin, not shikikin"
high likelihoodThe landlord or agent characterises money the tenant paid at the start as 礼金 (reikin, key money), which is a gift and is not refundable, rather than 敷金 (shikikin), which is.
What answers it
The two are legally distinct and the contract and receipts will say which was which. Shikikin is a security deposit and the Civil Code now defines it and requires its return, less what the tenant actually owes, when the lease ends and possession is given back. Ask for the contract clause and the receipt, and check what each sum was actually called at the time.
"The property needed cleaning and redecorating"
high likelihoodThe landlord charges for cleaning, carpet wear, scuffed paint or tired fittings and treats the deposit as a refurbishment fund.
What answers it
Fair wear and tear from ordinary use is not a recoverable loss in any of the regimes this product covers — a deduction must reflect damage or a breach beyond ordinary use, must be evidenced, and must be reduced for the age and remaining life of the item. Ask for the invoice, the check-in and check-out evidence, and the calculation.
"Prove you did not cause it"
high likelihoodThe landlord asserts damage and expects the tenant to disprove it, often without a check-in inventory.
What answers it
It is the party seeking to keep the money who must justify keeping it. Where there is no dated check-in record to compare against, an adjudicator has nothing to measure the alleged damage from, and the deduction generally fails on that ground alone.