Android APP Contacts

I'm in need of an app that does the following: 1. Must read a text file which contains name and phone numbers example: julian,+573202259042 eduardo,+573164658701 2. After reading the file you must create contacts with that data but you should only create the contacts that have whatsapp, the others should not be created. 3. If there are previously created contacts, you must delete them all, only the contacts of the file that have whatsapp must be left. 4. After creating contacts, you must generate a text file only with whatsapp numbers. example: 573202259042 573164658701 All the numbers must be without the "+" sign Must have the ability to adapt a presentation logo to the beginning of the app. I need the source code, but first I need to see what's working! I will only pay when the app is ready and I try it the freelancer shows me that it works. I will only pay the value offered for the project!