I made two call from St. Barth's( Caribbean island belonging to France) on November 17th, 2010.
Both calls togeteher were less than two minutes and they were directed to romania. When I attempted the third call I was told by an operator that he can't bill my credit card and therefore I won't be able to make further phone calls using that card.
But surprise. Few days after I was charged on my card the amount of 175 euro( aprox. $220) for a total of four transactions, each of these being more than 40 euro. So four transactions for just two calls totaling two minutes( probably shouldn't be more than 10 euro if they charge 5 euro/minute).
This is the biggest theft I have ever experienced and I contacted the callinf.com for a refund but I will definetly make everything to sue them.
Do not ever use these public phoes. IT IS A HUGE SCAM.