NYC housekeeping coming in and using phone?

We’re staying in a hotel in New York. We put the do not disturb sign on our door indicating that we didn’t want our room cleaned.

A housekeeping worker saw us walk by and return to our room, then knocked on our door and asked if we wanted our room cleaned. We said no and she said “Let me get you some towels.” She came in and changed the towels took the garbage out but what was weird was that she took the hotel phone, clicked a few numbers on it, then left the room with the phone for like a good three minutes and then came back and put it back. What does this mean? The vibe was weird. It was odd that she kind of insisted on coming in.