Seeking Professional in Android App development and Payment Gateway Research

Please READ CAREFULLY: This job isn't for an app development but strictly research on a project were working on for an app. OUR BUDGET IS $100  Who is Required: We are looking for a highly established an well versed Android developer with excellent app developing skills and payment gateway knowledge to research and help us understand a solution to a problem we have in our conceptual phase.  Work Required: We are working on developing an app that will utilize "MPesa" as its payment gateway. Mpesa is a popular mobile payment gateway used in Kenya, Tanzania and Uganda. (Please research online)  The goal is to allow users to buy credit using Mpesa via the app. So if someone spends 1000 shillings then they will pay through Mpesa from our app and if their payment is approved, they will get 1000 points in their account.  Also a user must have the ability to withdraw their credit straight into currency and directly into their Mpesa account. So if a user has 1000 points in their account and want to transfer their points then 1000 shillings will be transferred to their Mpesa number account.  We need a developer to research and see how this can be handled with ease by the use of either Mpesa or any supporting API platforms. We are open for suggestions and an approach that is very simple and cost effective. Serious freelancer only and a portfolio/resume must be provided. Required: freelancers to provide and show portfolio or resume of their past and current work. You will be automatically rejected if you fail to provide this. Thank you.