Hello vdbhb59 ,
we have quickly reviewed your request internally as an exception, as we do not provide official support in our forum.
This option is currently not available in your case as you have an outstanding balance—however, this balance is too low to make a credit card payment. We would like to point out that we do not set the minimum limit for credit card payments ourselves; this is done by our payment service provider.
Your request is already being processed internally – we are reviewing an option and will get back to you shortly in the corresponding ticket.
Once this is done, all future invoices where the invoice amount exceeds €0.50, the option to pay via card should be displayed again.
Thank you for your understanding.

Kind regards
Sarah & the netcup team