Help with credit cards payment on a publlic phone?!!

Hello, everybody!

I made the only two minutes call for abroad (East Europe). For this I followed by a picture instruction shown on the public phone body. I.e. I inserted my VISA credit card, waited a bit, than returned it back and start to call. The phone displayed the cost of this call euqal to 1.7 Fr. To my surprise, when I checked my VISA account, I found that 50 Fr (!) was removed by "VPD Swisscom /PAYPHONES SERVBERN SWISSCOMCH".

Can somebody explain me what is wrong and can I return the money back?

Thanks beforehand,
Uri,
Villigen, Switzerland