If you want to accept payments via mobile phones, you need to deal with a local mobile operator.
You need to have your own web server and you need to write a code using the API which is provided by your local mobile operator.
The code has to process a text file which has access codes to our system. This is provided to you in form of voucher codes which you need to buy from us first for 30 of the end user price. After you have them you can export them to csv which you can put on your web server and you write a code which gets one access code to the csv and deliver to the user via sms after the user paid with their mobile phone.
On the hotspot splash page you can write instructions to users like 'Send an SMS to '+4564646464' with the text 'PAY30' to get 30 minutes for $3.