I keep getting charged 100 euros a month even though I cancelled my plan 4 months ago

If you go to https://account.adobe.com/plans, you will see your active plans. When you cancel a plan, you get an e-mail to confirm the cancellation. If you did not get that e-mail, there was a problem with the cancellation, and it did not succeed. BTW: I'm not aware of a plan costing 100€/month. The closest is a monthly Creative Cloud All Apps subscription.

Hi there,

We appreciate you writing in. Happy to help!

We have checked your account and we see that you have an active Creative Cloud All Apps subscription under the email address associated with the community.

There is no other subscription that has been cancelled recently. Please check if you may have signed up with an alternate email address.

Please log in to the Adobe account and you should be able to see all the active plans.

https://account.adobe.com/

In case you want to cancel the subscription, please follow the link below which has the steps on how to cancel a subscription.

https://helpx.adobe.com/manage-account/using/cancel-subscription.html

Also, please read the article to learn about cancellation terms for your subscription.

https://helpx.adobe.com/manage-account/using/creative-cloud-subscription-terms.html#cancel

Since, this is a community forum, if you need any further help regarding billing or account as suggested earlier please conect with the Support team.

Please do not share any personal/confidential information like email ID, bank details, etc here. This is a public forum.

Hope the information was helpful to you. Please let me know if you have any further questions.

Sincerely,

Rashmi Swain

these are user forums and you should contact adobe support.  there are 3 ways to contact adobe; chat, phone and twitter:

chat:
use a browser that allows popups and cookies
and click here, https://helpx.adobe.com/contact.html?rghtup=autoOpen
in the chat field (lower right), type AGENT
be patient, it can take quite a while to reach a human.

phone:
https://helpx.adobe.com/contact/phone.html

twitter:
tweet @AdobeCare

p.s. if you're contacted by anyone (via email or private message), it's much more likely to be a scammer than an adobe representative. ie, double check for an employee badge if contacted in the forums and look for an adobe.com domain in the email address if you click reply to an email. then check again and be very suspicious. any other method of contacting (or offering to contact you) is almost certainly a scam, https://community.adobe.com/t5/using-the-community-discussions/staying-safe-in-the-adobe-support-community/td-p/12919684/redirect_from_archived_page/true