I need an Android app developer

I need an Android app. I already have a design for it, I just need it to be built. 1. keep the call log 2. remove all other call related features kiki mobile will only transfer money 3. verification is not working correctly in the beginning 4. I want to add a numeric Pin feature before user can send payment after the user clicks send money 4 boxes will appear with a numeric pad 0 - 9 and user has to put in 4 digit pin for payment to proceed the user would create pin during original registration screen finally if user puts in code incorrect 3 times the user is locked out from sending payments for 24 hours