Hello,
I have checked the requirement along with the site you have referred. I am quite sure setting up this kind of application using a custom programming platform instead of a CMS based solution like WordPress. I am not sure if you want to develop this on WordPress. I have studied a bit on the ding connect API and I guess we can integrate that API to fetch country-based mobile recharge data.
Here you may need to have option to recharge other services apart from mobile as I believe. Please initiate the chat so that we can discuss the finer aspects of the project to get started with a solid project understanding.
Please note, the price and timeline I have mentioned is a placeholder for the time being.
Thank you so much!
Convergent Infoware