There are couple of most stringent countries, where each merchant is obliged to obtain license or registration allowing to run premium rate services. UK and Ireland are being most regulated markets, where unlicensed operation of services may lead to serious fines and revenue freezes. Therefore prior registration is always required as part of on-boarding procedures. Some approval countries require special on-boarding procedures and special attention to preparing service descriptions, such as Canada and South Korea.
Please take your time to familiarize with the list of most complex countries on the left side menu.