You guessed it.... the switch was on AUTO... don't ask how it got there, but once I put it on MANUAL we're back in bizHmmm, is stove on a thermostat? If not, is control board switch in correct position? Does the unit turn on and feed at initial startup and then ignite? If control board does not change settings, maybe a loose connector from motherboard to daughterboard... Hard to know what to do if not there seeing what the stove is not doing. What did the folks say that worked on it? Is combustion motor coming on and running? If its not doing its work, then the vacuum switch will not close, that will not allow auger to feed. Pellet stoves are all about gates, one has to be met so the next one can be performed. It's not a hard system to follow, but if one does not realize what is needed to happen for the next thing to happen, sometimes too its silly stuff, we've all been there. The manual troubleshooting can help too, just some people will not bother with it, cuz "they know how it works already". Unfortunately, I've been there too. Keep at it, it'll get looked at by the right person and she'll be back to running normally. A proper, full cleaning is always, always the first step.
!! YAYYYYYCan you believe the shop never suggested I check that switch which you vaguely mentioned?