Sorry, payment processing is completely handled by Google Play. Please share a screen record of the issue so I can take look at what's going on at your end. Thank you for reaching out!
Hi, thank you for the detailed feedback. May be you already know this but VPN requirement (in China) is because SB stores your cloud file metadata on its Firebase/Google server. That being said, do you think the upload/download speed is impacted because a VPN is required? Also could you send an email to support@swiftapps.org so I can follow up?