Hey there @yanghanbin
What is the exact issue you're having to purchase Kick 2 ? Is it a problem during checkout and what method of payment are you using ? If you're having an issue using a credit/debit card check this topic on the support page.
Available method of payment are Paypal account & Paypal Balance as well as credit/debit cards.
If you still having an issue to make your purchase, contact S.A customer service via mail using the following address email@example.com