It is a gym where classes are currently active. Before coming here, I talked to people with good English levels in the correspondence, but the people I am dealing with now do not speak English. I send e-mails to the people I talked to before, but there is no response.
In the documents I have, it says that it was paid for part-time 6 months of muay thai lessons. So there is no extra fee, you pay for the lesson, not the visa.