Here are the support telephone numbers (office hours only) and e-mail addresses (24/7) for any issue with the SMS payment:

CountryHotline TelephoneHotline Email Address
ArgentinaNo Telsupport.ar@zong.com
Austria0820 252 25support.at@zong.com
Australia1-800-667-084 (Voicemail)support.au@zong.com
Belgium0800 73336suport.be.fr@zong.com, support.be.nl@zong.com
BrazilNo Telsupport.br@zong.com
Canada866-945-7469support.ca@zong.com
Switzerland0848 123 767support.ch.fr@zong.com, support.ch.de@zong.com, support.ch.it@zong.com
Czech Republik0 844 44 484support.cz@zong.com
Germany800 767 26628support.de@zong.com
Denmark8088-9816support.dk@zong.com
Spain911436075support.es@zong.com
Finland942597805 (Voicemail)support.fi@zong.com
France00800 767 26628support.fr@zong.com
Hungary01 888 6292support.hu@zong.com
IndonesiaNo Telsupport.id@zong.com
Ireland19010156support.ie@zong.com
MexicoTelcel: 01 800 699 1515, Movistar and Iusacell: 01 800 699 2020support.mx@zong.com
Netherlands800 767 26628support.nl@zong.com
Norway854 499 39support.no@zong.com
New Zealand0800-448723support.nz@zong.com
PeruNo Telsupport.pe@zong.com
Poland012 432 68 60support.pl@zong.com
Portugal707780302support.pt@zong.com
Russia8-800-3339008support.ru@zong.com
Sweden840309962support.se@zong.com
Turkey0212 478 00 77support.tr@zong.com
TaiwanNo Telsupport.tw@zong.com
United Kingdom0870 7370 030support.uk@zong.com
United States888-722-8035support.usa@zong.com
VenezuelaNo Telsupport.vz@zong.com
South Africa861106472support.za@zong.com