The lock on my room is not working.
ser-ra-TU-ra — four syllables, stress on the third.
Report this immediately — a malfunctioning lock is both an inconvenience and a security issue.
'Serratura' (lock) comes from 'serrare' (to lock/close). 'Della mia camera' = of my room — 'della' is 'di + la'. A broken lock at a hotel is a priority maintenance issue and staff will respond quickly.
La chiave magnetica non apre la porta.
The key card does not open the door.
Key cards are easily demagnetised by proximity to phones or credit cards
Mi sono chiuso fuori dalla camera.
I have locked myself out of the room.
A common problem — go to reception for a replacement key
La porta non si chiude a chiave.
The door does not lock.
A security problem that must be fixed before you sleep
Hotel key cards are demagnetised by credit cards, phones, and even some medication strips. Keep them in a separate pocket from your phone and wallet. If the card fails, take it to reception rather than forcing the door — replacement takes less than a minute.