Hello Ursula,
Thank you for reaching out to Microsoft Community, Regarding on you issue/concern "Onedrive storage despite subscription 365 only 5 GB". did you try to sign out and sign in or did you confirm your subscription if active? did you try the web version of onedrive? Visit OneDrive.com then Click the gear icon > Settings > Options > Storage.
See if it reflects the correct quota (should be 1 TB).
Please let me know if it works. I await your response.
Warm regards,
JayMark.D | Microsoft Community Support Specialist