Paid service/ Integrating 3rd party payment provider

Question:
I need a quote for integrating external APIs (possible long-term cooperations)

Product:
Wix Studio

What are you trying to achieve:
Location for the eCommerce website is in Serbia and Wix doesn’t allow any payment providers except Paypal for this country so I need custom integration. As I’m planning to create more websites for this country I will need someone who can do it on a regular basis.

What have you already tried:
I have tried using Wix Marketplace but I just got bunch of template automated emails.

Additional information: