Sign the inventory and condition report only when you understand everything in it. If uncertain about something, don't sign it or do so only with a clearly stated provision. In this case, also make a statement concerning the items not acceptable to you with a registered letter, and perhaps even turn to the local Tenants' Association.
Retain all records including a copy of the report as signed and dated by you and the landlord as well as copies of your letters along with receipts for registered post. There is no legal requirement to sign a handover report. If the landlord declines to accept the apartment, send him the keys in a registered letter.