@randahl People with very outdated contracts, without int. roaming incl. can have such issues especially in Switzerland, because this country is a bit specific in the terms of mobile network use. You need to be aware and careful in which canton you are and what prefix you're using for dialing. 0 is not a same as 00. Zero is for calls within Switzerland only. Double zero is an international call prefix only.. If you replace them by mistake, you may have huge problems and a very big bill to pay.