Will the artists‘ social insurance (KSK) accept the credit note?

The credit note is an adequate replacement for invoices.
The only difference is that the issuer / originator is reversed, meaning that jovoto releaves the winner of the work of raising invoices.

If you need invoices with serial invoice numbers for the artists' social insurance (KSK) you can create a pro-forma invoice after you received jovoto‘s credit note.
You do not need to send this invoice to jovoto, it is just for your own bookkeeping and can also be handed to the artists‘ social insurance (KSK). Just make sure that you refer to the related credit note on your pro-forma invoice. The best would be to put the credit note number on your invoice, stick it together and take it to your files
If you create a pro-forma invoice, please make sure that both documents are noted in your bookkeeping.

By the way, all invoice relevant data can be easily included in your invoice by using copy
and paste.