If no mutually agreeable solution can be found, you can apply to the Swiss Banking Ombudsman, a free and impartial information- and mediation service.
Generally, the Ombudsman only gets involved after the client has made a complaint in writing to the bank and the bank has had the opportunity to respond.
Swiss Banking Ombudsman
Bahnhofplatz 9 Postfach
T +41 (0)43 266 14 14
F +41 (0)43 266 14 15