Blech. You should never put flavored coffee in most coffee makers (or grinders) as getting the flavor out is an exercise in frustration. Keep one grinder and brewer for the flavored stuff so you don't pollute the good stuff. It doesn't have to be expensive, a hand grinder and aeropress/pourover/french press get the job done.I am not sure of the model, but my cousin in Poland had to send his coffee machine in for service because it wasn't working anymore.
Turns out that the pumpkin spice flavoured coffee I had sent him was causing the damage. They were told not to use any flavoured coffee as the oils in the falvour would clog up the internals.
Not sure if this is the same here.
I don't entirely agree with the repair shop. Coffee is oily already and that can gum things up. Too long between cleanings and it is like an old carburetor full of black varnish.