the OP just wants to pay his electricity bill. apparently the PEA bills have a QR code (dunno, I'm MEA) so easiest thing for him to do is get the BBL app.
It's not complicated at all, login to the app, press Scan and hold it over the QR code and hey presto!
Banking with BBL and not use the Bualuang app is cutting your nose off to spite your face.