Not possible in winter?

Hello, wanted to ask today at the “Friendly” (well, more or less) winter tire prices for the up my wife. As summer tires are from factory “185/55 R15 82T”. Wanted to know the price for this size, or “175/65 R14 82T”. Prefers steel rim, because my wife slightly overlooks curb stones in the snow. I was then told that only the size of 165/70 R14 82T registered in the bill would fit on the up. On my note of the delivery size (185er) and the still 5 other size I then got the answer, which only applies to summer tyres (?) for winter tyres went only the 165 (others they wouldn’t have). I know that not all sizes have a snow chain clearance, but so? In the EC certificate there is no restriction (summer/winter) with it. Can anyone tell me if the statement of the contract workshop is correct, or if “only” should be sold. Thank you.