I am shocked, Jenny, but also quite excited.
Shocked, obviously, that a tutor can complain that a student is learning to speak naturally, and shocked that a tutor can belittle a student, and make them feel bad about trying to learn a bit more than is taught in class.
But excited by two things. One that you have taken this on the chin and rather than letting it affect you over time, coming here and asking other people for advice. Thats says to me that your motivation is bigger than your bruised ego, and that is a sure sign of an chiever.
And secondly, that you are already working our how to keep on getting the advantages of class (company, conversation etc) despite this quite unpleasant experience.
I think your tutor sounds as though they are a bit unsure of themselves, and that you may be asking questions that the tutor doesn’t know how to answer. If that is the case, then it’s good that you don’t like confrontation, because confrontation would only go one way, and you would both lose out. If you are able to keep going to lessons (great advice above - if it’s upsetting you / giving you negative feelings towards your Welsh, etc, get out of there now, money or no money!), then maybe it would be a good idea to write your questions down and ask them here, so as not to challenge your tutor, and practice something that may very well help your Welsh quite a lot, which is to use class Welsh in class - filling any gaps with SSiWels of course! - and using a natural mix out of class. This will keep your tutor happy, help you with any tests etc that may be administered by your tutor, and help any of your classmates who may get confused by non-class Welsh at this early stage.
It will also be under your control, which will build your confidence in using Welsh, and mean that you get used to different forms for different situaitions, which again is an immensely important part of a first language speakers repertoire, but rarely features in early learners, or later stage learners who only speak with other learners.
In other words, use this as an excuse to improve your Welsh in different ways that keep your tutor happy. And rememerb, f some of your class Welsh slips into your lessons, don;t worry - you don;t have to use the same words as us, you just need to be happy that you’ve said the same thing as us (if you see what I mean).
Anyway, do let us know how your experiences devekop, whether that’s “no it was too stressful”, and you’ve decided to walk awa fro the lessons, or whether you’re trying different strategies in calss to still get where you want to get. I’m sure you won’t be the last to be in this situation!
Good luck, and whatever you decide, remember, it is your decision. Enjoy it!