Is it illegal for a company to keep your debit card details?

Yes, it can be illegal for a company to keep your debit card details without proper consent and security measures. Regulations like the Payment Card Industry Data Security Standard (PCI DSS) require companies to handle card information responsibly. Additionally, data protection laws, such as the General Data Protection Regulation (GDPR) in Europe, mandate that personal data must be stored securely and only for as long as necessary. Always check a company's privacy policy to understand how your data is managed.