Hello Lukas,
Thanks for the job invitation.
I am an expert Cs-Cart Multi vendor sites developer, working for last 7 years. I have studied your job description and checked given URL. I can help you to build a CS-CART MVU Add-on for connect the Banggood API.
As I am Having excellent knowledge in themes development/customization, Add-on development, Payment Gateway implementation, Cs-Cart multi-vendor configuration, etc.
Regards