OP, try this helvatel.ch .
I have used it for years.
Google hangouts
Facetime if you're apple inclined.
Why would anyone phone?
The only sign that shows they belong to the same bunch: They all share the same mail address in St. Gallen and the same VAT number. On the Internet, they all act as if they were different companies. Maybe they hope, once one of their branches has pi$$ed off customers, they will switch to another provider, which most likely belongs to the same background company, because they cover more than 80% of the Swiss market.
SG address is probably post restaurant (not for visitors), and all seemed to owned/operated by a Dutch holding company (Solaris Systems BV, Amsterdam, including Solaris Systems.co.uk)
However if it works for cheap calls, then no harm done.
The SG address is an office building just across the street from the city hall (Rathaus), actually a prime location with everything from labor union and law offices through retirement pension consulting to surgical practices and the dental practice of a kindergarten mate of mine, but no Solaris nor any other company that looks like it could be active in the telecommunication business.
Yes, it's cheap, and usually it works, although to the USA it sometimes doesn't work for weeks, and I've never gotten a reply to any of my e-mailed complaints. It's just weird that they pull off such a game of hide-and-seek. What are they concealing?
[In case my contributions to the forum abruptly stop in the near future, you folks know what to tell the police.]
My mother was pretty tech savvy and we were able to Skype her but for most of my older relatives ( in their 80s and 90s ) it's an alien concept. Landline calls or snail mail are the only ways for me to keep in contact with these members of my family.
To the UK you'll pay:
Landline 0.009 CHF/min
Mobile 0.140 CHF/min
SMS 0.056 CHF/min