Running low? Add more data to the eSIM you already have. Look it up with your email and order reference, pick a size, and the data lands on your current eSIM. No new QR code, nothing to reinstall.
Where to find this: open your Slashtel confirmation email. Near the top it says "Order ABCD1234". Enter those 8 characters. It is not your ICCID or the long eSIM number.