Unconsensual sign up for “premium SMS”

Hi everyone! Today I noticed that I have a weekly CHF 9.99 extra service bill in my Sunrise invoice.

On further investigation, I found out that the service bill is for a "premium SMS" service from "DIMOCO" (a provider of payment solutions for businesses). The SMS in question from the short number 2233 fell in my spam SMS folder, which is why I wasn’t seeing them up to now. Now I see that there were two SMS 4 weeks ago, one with an activation code for "Cell phone learning" subscription, and another one thanking me for activating the subscription.

The thing is, I never did it, and today is the first day I actually saw these SMS. I’m also pretty certain there was no third-party access to my phone who could do it (and I wasn’t even in Switzerland the day they signed me up). Anyway, overall I got three CHF 9.99 bills totaling CHF 29.97 until I canceled the service today and blocked value-added service in Sunrise altogether.

So, my main two points in this post:

• If you didn’t yet, block value-added services with your mobile service provider to be on the safe side. Also check your spam SMS folder occasionally in case you do get signed up for something fishy, so that you can cancel it quickly enough.
• Is there anything I can do to properly report these activities? Sunrise told me that they don’t have a say in it, and I may write a formal arbitration request if negotiations with "service providers" fail (which seems pretty likely to me). The arbitration request, as I understand, requires CHF 20.00 filing fee, and its decision is not binding anyway, so service providers may choose to ignore it. Any options for me if it fails, other than going to court over CHF 29.97?