Presuming that by cancellation, you mean that KM cancelled, not you. If that is the case, then EC 261/2004 requires that the carrier initiate a refund within seven days of your request.

If it does not, simply file a chargeback with your credit card issuer (bank).

Make certain to do everything in writing and to provide the following:
- Copy of your e-ticket receipt
- Notice of cancellation.
- Your request for a refund, noting that you are entitled to a refund under EC 261/2004.
- That email from KM advising that it will make a refund (simply outside of the legal requirements).

Do not wait for a refund and do not waste time on the phone with KM