No offense. It's more that I just don't have time to keep telling you things you can work out yourself. First off, be logical, my issue was with an iPhone 5 and white MC and what i learned form Cisco was HUGE. The White MC has a defective firmware that doesn't work well with at least iPhone 5's. 6's weren't released yet. He was on the team that found and fixed the problem which I stated and so he was at "action central" of the problem and fix in a way that even if ATT were on the ball, they couldn't know.
But you have a Black MC and legacy iPhone 4s, so there's no telling what your issue is and my reason for sending you to Cisco is obvious. You need to know what if any issues exist between older iPhone 4 and Black MC. ATT will not know this. Cisco might not either, but it's a shot. If you can get thru and Cisco tells you the 4 did work with the white MC but doesn't with the firmware in the black MC, or that they didn't even test the 4, then you might have enough info, or lack of info, to make a decision to stop using the MC or upgrade to a later iPhone 5 series or 6.
But my concern was you weren't connecting these dots from my experience and asking me to repeat my iPhone 5/White MC conversations which have no bearing on your case which tells me you're not reading or not assimilating and my input and I can't keep writing you if you're not going to take my words and experience and act on them. I can't help you more than I have. AND I stand on my thinking that you need to understand the relationship between the iPhone 4 and Black MC which I believe Cisco is a better source for info than ATT unless you find a phone tech brain at ATT who just knows tech inside out.
Keep telling your story to the front line at CIsco, tell them you know they're not supposed to offer ATT customers MC tech support but your hands are tied because you're not getting the info you need from ATT and the only source for that info is Cisco. Ask for supervisors if they say no. But keep pushing, politely and acknowledge they are doing you a HUGE favor outside their agreement with ATT. Please Please Please help? Keep pushing. ANd keep calling back as I did until I finally got a sympathetic ear who connected me with a tech on the MC development team. PAY DIRT! You can do it. Persistence!