iPhone 15 Pro only rings once

I am writing to seek assistance in resolving an ongoing issue with my iPhone 15 Pro. I have visited the Apple Highcross store on four occasions regarding the same  problem where incoming calls sometimes ring only once before going silent. Despite the staff’s politeness and their efforts—including adjusting settings, resetting the phone to factory settings, and advising me to wait for a software update—the issue remains unresolved.

I primarily use this phone to support a charity that assists individuals dealing with bereavement.  Missing calls, especially when the phone is in my pocket, can cause distress to those in need of our services. 

Given the persistence of this issue and my multiple visits to the store, I am reluctantly reaching out to request a definitive resolution.

I would have expected a company of Apple’s reputation to address this matter more effectively. 

Please advise on what can be done to rectify this issue as soon as possible. I look forward to your response.

Best regards,

Suleman Nagdi