I just use a stripping knife to pull the undercoat out (occasionally, I've been bad and used thinning shears, NOT cutting, but opening them up "raking"). Here's an idea of what mine looks like (I think I have medium slant tooth, I would have to double check the size):
Mars Pet Grooming
Furminators work, I mostly used it on a dog who had an abundance of undercoat.
I don't use the above to actually strip tho, I prefer something similar to a pumice stone (easier to pull and doesn't break coat).
Did your groomer pull her all the way down to her undercoat? After I do that, I don't touch them for about 4 weeks (when that first little layer is growing in), and then I pull undercoat off, and don't touch for about another 4 weeks. By that time, they should have a hard jacket but its all one layer pretty much (that's when I trim once a week to build the layers to "sculpt" the dog more). For pets, much easier. I would pull down to undercoat, let the one layer grow long, pull down to undercoat again, repeat LOL.
I can ask a friend in Canada if she knows anyone in your area (she's in Ontario) if you would be interested in learning about rolling a coat, building layers, shaping, etc. yourself? Would Teagan's breeder be willing to help you?
and after posting I realized this thread was from all the way back in March, oy vey, only looked at the last poster's date.