Keypad not working during call

My keypad doesn’t respond all the time when I need to press a prompt to continue. What bothers me is that there are other posts about this specific problem on here with no solution and superficial advice. This has been an ongoing problem for me with iPhones and it’s starting to get frustrating. Once I called Apple about a problem with my Mac and I asked if the person on support could fix the problem, his response was “of course we can we’re Apple”. However, someone posted about this same exact issue over two years ago, but if you’re Apple why is this not fixed yet? This has happened with my iPhone 4, 5, 5s, 7plus, and now XR. How many phones will I go through and you guys make obsolete before you fix this?