Oneplus is temporarily disabling credit card payments at oneplus.net. The only place that both of those credit cards had been used in the last 6 months was on the Oneplus website. OnePlus is investigating around the clock. PayPal is still available, and we are exploring alternative secure payment options with our service providers. An official statement: https://community.oneplus.com/thread?id=752415 Please note that issue is still being investigated and that thread will be updated by admins.”]
Source: https://forums.oneplus.com/threads/credit-card-fraud.747206/