What make is your machine?
I usually go direct to the manufacturer - most will have either their own repair service, or a local partner.
Is there a sticker somewhere on the machine, either on the top corner, or perhaps inside on the door ring? This is usually where you can find a service phone number to call. You'll likely need the make and model number when you set up a service appointment.
When getting repairs done, I usually figure on CHF 200-300 for labor, plus parts. Depending on what's wrong, bills have mostly been under CHF 500. (When it's been more that CHF 500, I usually start to think about replacing it with a new machine...)
If the manufacturer tells you that it will be longer than a week for an appointment, ask for the name of a local firm - that usually either gives you a contact who is more motivated to do the job, or 'miraculously' frees up an appointment in the next few days.
The key thing is to insist on a time frame when setting up an appointment. Most services should be able to narrow it down to a half day at least - so you aren't left twiddling your thumbs all day long, waiting...
Good luck.