Please write me a mail whenever you have questions, found a bug, or have any new ideas for future versions.
Mail to Hauke:
You can contact me in English or German.
If you have any questions that are related to payments (credit cards, PayPal,...), please contact my payment provider. As I am "just" the developer, I cannot answer these questions myself:
Contact payment provider (PayPro Global).
Are you looking for a serial that you purchased in the past? Please take a look at "How to find a serial?"