May look spooky, but is effective
Used the HSR top-up service for my monthly express pass needs as a trial run. Log-in top-up may look like a rather sketchy method at first glance since you've gotta give your credentials and password, but they handle your order pretty efficiently and I've had no other issues whether it be account security or payment-related stuff. Cooperation with the service takes about 5-10 minutes tops. After the downfall of many other sites like lootbar, it's pretty much one of the last remaining sources you can trust for cheaper top-ups 🙏