@Marcin.wawr

Welcome to the Magix user to user forums, so not a contact for any Magix staff and no-one who posts here can help you, sorry. In addition, you should never post confidential data, like your address, email address or serial number to a public forum like this one. Hence, I have edited your post.

You need to email infoservice@magix.net with full details of your current subscription and ask that they cancel it. Depending on when your cancellation takes effect it may be that you will have to pay at least one more month's subscription. (That is a standard requirement of the subscription service and depends upon when the cancellation actually takes effect.)

Jeff
Forum Moderator