I’m humiliated !

In a good way, kinda, lol.
I have this monthly commercial job I clean and they have this elevator landing on 7th floor that gets TONS of traffic going out from the office to the hallway to the restroom, they don’t have me clean the whole thing, just from the entrance / exit from the office to the hallway, I’ve experiment with this carpet too many times, from regular power burst, to firestorm boosted with ultrapac, nothing seems to get the traffic areas all the way clean, we call them wear and tear right ? Well I was firm to that until last night, I went there and they had informed me that the building had the area deep cleaned for them, I was blown when I see the carpet, it was actually CLEAN !! Much cleaner than any of my cleanings, I asked the company’s rep, she said she doesn’t know what they cleaned it with, my first and best guess was bonnet cleaning.
So as we were cleaning 5th floor, I met the janitorial workers, we know each other pretty well, we see them every month, I asked them hey do you know who cleaned the 7th floor landing, they said oh yeah, we did, well Ricardo did, I asked Ricardo wow man, you did a great job, what did you use ? He was kinda paused for a second or two, I thought because he didn’t know what those machines are called ( buffing machines ), I suggested it, buffing machines ? He said yes, then the lady jumped in, she said he cleaned it with a mop
I wasn’t sure if I should laugh or cry, lol, I looked at them with a straight face for a few seconds before asking them, a mop ? I proceeded with a smile and told him, well you did it, it looks a whole lot better than my cleaning for sure, then the lady told me, it’s better if you don’t touch that carpet again, let us clean it, lol.
Now it comes an issue that I don’t know how to solve, I don’t mind losing that cleaning, I don’t feel hauling my portable up there just to clean 180 sq ft of carpet, but how do I break the news to my customer, I don’t want to tell them that a mop and bucket of whatever chemical they use beat the crap out of my $ 2500 portable, chemistry and knowledge.
What would you do ?

I guess my concern would be exactly WHAT they put on the carpet. Maybe the stuff will start falling apart now?

I'd be concerned, really, about what chemicals they used. Who know if it won't eat the backing or the nap right out of it. It would suck to go up there next time, and chunks of the carpet start getting pulled up with your wand..... I wouldn't want to take the blame on that!

My buddy that has a hard surface cleaning business was helping me with that job and he also wonder what chemical did the guy used, he was very concern also.
I guess I have to let them know that it's better if they have janitorial company handle that portion of the job from now on, since they seem to do a better job, but what if they still want me to clean it in the near future, then I guess I have to be upfront about this ( explain the risk that you mentioned ).
Sh!t, this situation is just bad all around.

A mop will never provide any recovery on carpet, not even commercial, so regardless of how it appears it isn't clean. It was probably just a heavy dosing of encap and follow-up vac. He is more illusionist than a cleaner in my estimation as are many others like him.

On that kind of job, HWE followed by encap really works out well if there is any fiber left.

Dawn dish soap, scrub real good to make it foamy; then use the shopvac.
I watch youtube; seen it....

Sheet, you guys really made me feel like I shouldn’t clean that carpet ever again.