Hello, I bought Halbtax Plus 1000 some time ago and I would like to “top it up” - buy another Halbtax Plus 1000. I stil have 0.80chf in my balance. However, I cannot top it up or buy another Halbtax Plus. When I try to buy a new one, I get an error message. And I cannot see any option to “top up” in my settings. Is it possible to do it at all? Or do I have to go to the SBB counter at the station and do it there?