Hi @ileauxchats ,
Welcome on the community forum !
I'm noticing that you're writing in English on the french community forum so I'm answering in English but I can switch to French if you want.
In order to cancel your subscription to the third party app "TrackingGenie" you'll need to delete the app from your store. You can see all the applications installed on your store from your Shopify Admin under "Applications". Everything linked to billing cycle for third party apps is explained in our documentation here.
"TrackingGenie" is a third-party app so we can't provide more support than that, however you can still contact their team, their support information is available from their page on our app store here. I hope this answers your question, I'm still available if you need anything.