TN VISA Approved but then put in a confusing limbo for no reason
So my friend has a TN Visa and is a Mexican national, he has been working 4+ years without any issue, working 10 days in the US and resting 4 in Mexico, flying every time, global entry approved, all renewals are a piece of cake.
Everything was good, until he changed his job, of course he had to change his TN visa, at his job told him about a process in a border city's US embassy where is not issuing a whole new visa, is a change of employer and information with the same visa, he investigated it was a common process, other people from his previous job and future job has done it, he went to the US embassy asked if everything was good for his new job, the US embassy assured him everything was good to go.
He had his first rotation, a week, no problems. He went back to Mexico as part of the rotation, and then had his second flight, right after he scanned his TN visa at the global entry a immigration police officer just saw him real quick (he's very brown) and told him he was gonna be interrogated. They told him the process he made in Mexico's US embassy is only for Canadians, and he's lucky they were not banning him from the US, he only got his TN visa cancelled because he was supposed to get a new one not the change that only Canadians are allowed to do in Mexico. Luckily he already had a visa appointment because he was nervous something like this happened, so he waited just a couple weeks.
Now in the US embassy they told him, immigration has no power to scribble in it or his passport nor cancel the TN visa, especially when he had no bad record at all, not given a valid reason, but he can't also apply for a new visa since that one was not cancelled correctly but he can't use the one he has because It has written all over it "CANCELLED" and has scribbles with pen.
They only told him "we'll review the case and contact you back"
No date given, he might lose his job because he can't do WFH, his mom depends on him and her health bills just keep arriving.
Does any one know what happens in these situations? Could this be resolved quickly? This could result in a visa completely cancelled and banned ? Who could he reach out for his case?