Problem after 8.3 update. Apple no help at all.

Hello everyone I'm new to here but I need help. I have had an iPhone since the original 2g and have always been happy as they have always worked and done what I needed. I even upgraded to the iPhone 6 128gb but found myself using my old 5s 64gb more and more so sold the iPhone 6 and was perfectly happy using the 5s. Then I updated to iOS 8.3. The fault I'm having is that I can no longer make Bluetooth calls. my phone connects to any Bluetooth device and even will play music and is controllable using said Bluetooth devices but when I make a call it goes silent, if I then press the audio key and select either iPhone or speaker the call is there. I have tried different devices all have the same problem. I have tried my wife's phone and it works perfectly on the same devices. I carried out a iTunes restore and set up as a new device, and still it didn't work. So then made and appointed with the Genius Bar at my nearest Apple Store which is over an hours drive away so drove up yesterday and tried to explain my issue but I felt that although the guy was very nice and friendly wasnt really interested or understood what my fault was. So he then carried out a restore using one of there macs and that should be ok now and have a nice day. I asked what would be my recourse if this didn't fix my fault and was told I would just have to buy a new device and then was offered a new contract. I have since tried my phone and still is the same. I drive a lot for work and need the phone to connect to my car kit. Can anyone help or advise. I am really disappointed in Apple with this.