With over a decade of experience in software development, particularly in the Telecom Domain, I understand the urgency and complexity that can arise with payment gateways. My proficiency in Java, Web Technologies like EJB, JSP, AJAX, among others are testament to my ability to navigate complex systems; an essential skill to addressing your current Apple Pay issue efficiently.
While my skills extend beyond the Apple ecosystem, I am no stranger to iOS development. Having regularly developed for iPhone and acquired industry knowledge on mobile payment frameworks like Stripe, I understand what it takes to make sure every aspect of your application runs smoothly. Additionally, my experience in SQL-PL/SQL programming further supports my prowess at analyzing databases and troubleshooting critical issues.
In terms of methodology, my familiarity with MVC Design Pattern gives me an edge by ensuring separation of concerns, maintainability of code and robustness of the system as a whole. It will allow me to quickly identify where the "The customer has not entered their payment method" error may have originated from, making for a thorough fix guaranteeing it won't reoccur. With my strong communication skills and knack for identifying finer details effectively, you can trust that I'll address your urgent need proficiently and with transparent communication throughout the process.