"using a hotel
Wifi Skype did not work."
That is not because Skype doesn't work. On the contrary, it works too well and too many freeloaders use all the bandwidth for Skype, so hotels, bars, coffeeshops, often block the IP range that Skype uses. The hotel is what "isn't" working, they're blocking how much bandwidth any one user can take up.
Any VOIP service
will work, the question is which one looks attractive to you & what internet service
you can find (buy or steal or borrow(G) to use it on. Many of them are 2-3c a minute globally when you can find internet
service to use them on. Assuming the internet provider hasn't blocked them too.