If your original charge was in a currency other than CHF, then your refund will be processed in that same currency. If the exchange rate between date of purchase and date of refund has changed, that is entirely your loss or gain. Your credit card issuer doesn't get the original CHF amount back from the merchant, so they won't pay out the original CHF amount to you.
You may want to talk to your issuer about seeing if they are willing to waive the 1.2% forex fee on the refund as a courtesy.