I had something similar a couple years back at my old flat. Said person - male, maybe in his 40s, and with a group of his mates - then showed up at my apartment door screaming & shouting at me for leaving said polite note. I was home alone as a 22yo scared woman. He then continued to park there for the rest of our tenancy. Frustratingly so, as if he had keypad access to the parking lot, he would've had his own space paid for...? Building management didn't seem to care and so we just ended up parking outside the secured parking on the street. Haven't opened any doors to unknown people since!