In the reseller panel, find the existing customer line and choose Renew or Extend. Confirm the duration, simultaneous connection allowance and current credit cost before proceeding. Extending normally keeps the same line and credentials and adds time. Verify the resulting expiry in the panel.
For a renewal through the website instead, use the same subscription email and select Extend Subscription. A different connection package may require new credentials. Contact support if the account needs a manual change.