Yeah, he mentioned that because we had some stuff at the bottom of the tank, but only a small amount. Might have been from when my daughter was here and using those too, because we certainly know to use septic safe everything, and he did mention those basically don't break down at all.
They just left and it is nearly a worst case scenario for us unfortunately. Roots got into the distribution box (it was completely filled with roots and dirt and was completely dry) and the roots grew up and completely filled a 20' 4" line all the way to the tank. They stopped there and said they'll likely have to replace everything from the box down. That means excavation, permits, and more or less a whole new system from the box down