Fix Multi Vendor e-commerce grocery mobile app

Job ID: 31786541

Budget: $30 – $250 USD

I already have Multi Vendor e-commerce grocery app which is developed on native android. The app is a platform where grocery shops can sign up and add their categories and products and the customers can add products to cart and checkout, there is not payment gateway. The app works fine but I just need to fix few things and also I need to integrate the Firebase opt messaging in the signup page. Also there is ready web admin panel which is developed on PHP and via this panel I can manage the marketplace (it is basic admin panel).
Also in future I want to build ios app same as the android (but now I only need to fix the android version).
I want someone with the following skills: Native android, native ios, core PHP, API, backend, google Firebase.
you can place an estimated price and later I will send you the apk for the app to check it and I will send you all the things I want to fix and then we have to agree on price. I want long business relation I am looking for good developers who can look after this project and get paid regularly.