Did they speak Swiss at the beginning, the end of the lesson or most of the way through? As it's a basic beginner's class your teacher could be just getting to know everyone, setting up a relaxed atmosphere and completely overlooked the fact you don't speak Swissgerman. Funny though, as I teach Swiss classes English the only time I speak German is to translate high German grammer into English. Often in beginner's class confidence is low and I have to go over High german grammer again as they have forgotton. Maybe your teacher is doing something similar.. though if that is the case shouldn't he/she be speaking in High german just to explain difficult points. Next week you could try introducing yourself and asking if everyone to speak high german so you could feel apart of things. But if your teacher continues to speak any swiss or german and not French and, more importantly, if you don't feel comfortable you'll need to find a better class.