Will I get in trouble after a language school cancels my visa solicitation?

tldr: Language school just sent my documents to the immigration office (I told them to wait lol), but I just passed a much better course. They said they are going to cancel it ASAP but am I in trouble?

Hi everyone.
I'm going to Japan in April as an student. Initially thought of going through a language school, I went through the whole process with them pretty early and everything was ok
However, my Japanese level is high and I'm interested in becoming an interpreter. I realized I'd benefit more from going to an interpreting course at a professional training college (専門学校).
I went through their really, really hard process and they just told me I have passed. Naturally, I'm really happy. I had told the language school I'd let them know if I would proceed with them as soon as possible and they told me they were sending the documents on the 18th. Today is the 17th, I immediately told them I would not proceed with them when I got the results.
The guy responsible for my process (he was a bit rude the entire time) told me they already sent my documents to the immigration. I talked to them a lot and let them know not to do that without my approval…
He said he will talk to the immigration office and cancel it ASAP.
I read on here that it doesn't look good if you apply for two visas at the same time and that you might be denied for that. The language school guy says there won't be a problem, but I don't know.
Although the senmongakkou will only send the documents in some days (possibily weeks), I'm really worried.
Is this bad? Am I overreacting?

by Illustrious_Ice_6487