@lilithanne The POS issue was due to poor signal, maybe. The small yellow ones are newer and had all sorts of issues (probably were never tested enough in the 1st place).

II had problems with them as well, but I never encountered any ticket inspector when it happened, oddly enough (I was prepared for the encounter though). I'm sorry about your fine, though.

They recently switched their carrier (apparently those work with SIM cards or something, as they seem to need a contract with a mobile carrier) - from Digi to Orange. They said this would bring better signal to the machines and lower their cost. Not sure about the former as I still had some issues, hope for them that the latter applies. 🤷‍♀️

Alternatively, you can get the 24pay app and use that to pay for your ride instead. You can even buy train tickets through it.