Change small feature for voip

Hello freelancers
I have ios/android voip app and already alive in appstore.
I need to improve small features. and looking mobile developer who has experience with linphone.

1. Change the colors on some of the screens including Dial Pad to have consistency with splash screen.
2. Show Rates for the destinations. Pull ‘them from the switch.
3. Integrate with TopUp platform CSQ.
4. Call via DID (default via DID without prompt)

Thanks