First, you need to get grub installed.
What exactly was the error? Are you efi booting? Did you have the internet connected while you installed linux?
If you efi booting, you can live boot Kali linux are remove the Debian folder from your efi partition. Thay should get you into windows depending on what you did when installing.
If legacy boot, reinstall grub using a manual method using a Kali live boot cd. Make sure it's Kali so the correct version is installed. There are plenty of grub reinstall threads if you use search.
