We have just migrated to a new upgraded billing system at https://billing.rahul.net/.
The old billing system remains active at https://billing-new.rahul.net/. (The -new suffix is not a typo.)
All data is being imported into the new system from the old system.
You may get mystery email messages from the new billing system, such as a message asking you to click to verify your email address. If the link you are asked to click points to somewhere within https://billing.rahul.net/, this tells you that this is a genuine email from our billing system, and not spam or phishing etc.