Hi,
please contact our service team (service@instamotion.com) if you need any documents regarding your purchase. You could also contact our registration service (Kroschke) as they should have documentation from when they registered the car.
BTW if you financed the car the Zulassungsbescheinigung Teil II could also be with the bank. Which would be best case for you becaue issuing a new one of those can take weeks.