Opencart Customization and Bug Fix

Our fully customized Opencart application needs some attention. I'm looking for a freelancer to help address a few bugs and add features.

Key Requirements:
- Fix a single bug in one area, to be discussed during intake
- Add payment gateway integration, specifically MTN MOMO
- Possibly add City/City_Area/GPS Location to Product's location

Ideal Skills and Experience:
- Expertise in Opencart customization
- Experience with payment gateway integration, particularly MTN MOMO
- Strong problem-solving skills to identify and fix bugs
- Familiarity with implementing advanced search filters and customer review systems

Please provide your relevant experience and approach to this project. Budget is flexible for the right candidate.