>… I think it is defective but I don’t remember what year I bought it….
follow the advice of @YariB
If the device is still under warranty, it can be replaced if defective.
for the guarantee the Swisscom Hotline can help
Private customers: contact by hotline, chat, message | Swisscom
Such. free 0800 800 800
For replacement (with or without guarantee) the best is to go directly to a Swisscom Shop
Swisscom Shops and store opening times – Help | Swisscom
“On apprend parfois plus d'une défaite que d'une victoire” — José Raúl Capablanca