I thought you could request to do a tax return even if you did earn under 120k? although a tax consultant is going to cost you around 1k chf, and then you might (read very likely) get a further tax demand. I am taxed at source and the only reason I got a tax rebate the first couple of years I was here was the expat allowances, but if your a permie you don't get those, otherwise I'd have owed the tax office about 3k more tax per year.