Hello maría35,
Welcome to Apple Support Communities!
If we understand your post correctly, you want to request a refund and also the subscription is not appearing in your subscription list. We're here to help!
We see you came to us from the resource If the subscription that you want to cancel is not listed.
If you find that the subscription is not billed through Apple and want to request a refund then this article will help: Get help with subscriptions not billed through Apple
If the subscription is billed through Apple then you can start your request here:
Request a refund for apps or content that you bought from Apple
Thank you for using Apple Support Communities.
Take care!