Obviously the people couldn't hear the doorbell, but many deaf people have some hearing in the very high or low ranges so I was instructed to kick their door and tap on it with a coin. Sometimes if the residents were near the door they could hear those sounds and would open the door.
It was obvious from the splintered wood at the bottom of the door that I wasn't the first visitor who had tried to get their attention that way. Although there was no response at first, I could hear people moving inside and kept trying in hopes they would move close enough to the door to hear the thumping and tapping.
Then a UPS driver arrived with a package for the neighbors in the adjoining unit, rang their doorbell, and looked frustrated when nobody responded.
In sympathy I spoke to him. "It gets frustrating when no body is home, doesn't it?"
The delivery driver looked at the splintered door, which I had continued kicking as I spoke, and replied, "Lady, just thank God you don't have my job!"