Motion Alert Tone no longer working

I installed 3 security cameras a few months ago, and set up different App Notification Tones for Front, Back and Side gardens. Initially these worked well on both iPad (iOS 13.6.1) and iPhone (iOS 12.4.8). Then the audible alert stopped working on the iPhone, and only the silent message "There is motion at your front" was received. Ring advised re-installing the App, which worked temporarily. However the same problem has recurred. I carry my phone everywhere, but not the iPad, and rely on the audible alert. After a lengthy conversation with Ring recently, when several possible solutions were tried, Ring now advise that I should buy a new phone in order to update the iOS. However today the Ring App on the Apple store still states that my phone is compatible, and that the App requires iOS 10.0 or later, which I have. Also, Ring's General FAQs state that "Apple devices must be iOS 9.3 or newer", which I have. I sent a formal complaint to help@ring.com but this returned a message that Ring no longer offers support via email! Can anyone please offer a solution so that I get App Notification Tones again on my iPhone? Also, how can I send a complaint to Ring without phoning them again?