You knew you had to supply this info back in July so why didn't you get this done before you arrived?

Master student (EU citizen) moving to Schweiz: questions

"This from ETHZ's website:

evidence of sufficient financial resources (not required if you entered Switzerland with a student visa). As financial evidence, the Migration Office accepts your own bank statement or (if you are an EU/EFTA citizen) a letter from your parents confirming that they will support you with CHF 1750 per month.

https://www.ethz.ch/en/studies/inter...ce-permit.html"

If other documentation is required they'll tell you and give you a reasonable amount of time to provide it.