Hello Bettina Ruff,
Thanks for your question.
To reactivate the subscription please take the steps below:
- Sign in to the Azure portal.
- Go to Subscriptions and then select the canceled subscription.
- Select Reactivate. The above is documented in the link below Reactivate a disabled Azure subscription
You can mark it 'Accept Answer' and 'Upvote' if this helped you
Regards,
Abiola