I had a similar problem with a nest next to my patio door. The nest
was under the siding and the entrance was close to the ground. I
placed the suction part of my leaf blower at the entrance to the nest.
The leaf blower would suck them up before they came back in or just
after the left. After about an hour my patio was filled with bee
parts. It took about three days with one hour at a time, by the third
day the bees coming out were very small. I'm not a bee guy but I
guess they started to pannic, sending any capable bee out to see why
no one is coming back. Good Luck