If everything for the bar oil was working right before the shop worked on it, I'd take it back to them, but it does appear that one of the complaints about that model with the auto oiler was it used too much bar oil. I'm not sure if there is an adjustment for that model or not. .
You can take the bar and chain off, and start the unit with the bar cover off and you should see oil coming out the little nozzle. I see mine oozing out just sitting there when I have the bar off and crank it over with the switch on off.
(Be careful reving it up. I would not run it long without a bar on it..it's easy to overspeed one without some kind of load on it and damage the innards.)
(My 290s usually have about 1/8-1/4 tank of bar oil left when I run out of gas)