Hi could you please show me where to post my question below, struggling with this?

Hi have a Sony KDL40R473 40-inch WidescreenFreeview Full HD LED TV  purchased April 2014, at the end of last year got the you view box through BT and it was set up with the HDMI lead, however after about 3 months the sound disappeared if I used a scart lead the sound came back, complained to BT who said to do a factory reset of the you view box which I did and still didn't resolve so sent me another you view box, the same thing has happened! wondering if there is a problem with compatibility of the HDMI port with the you view box, anyone heard  of this issue?

Would a Sony HDMI lead maybe solve the problem? any advice would be appreciated, BT were going to send another box but cannot keep trying new ones surely!  Many thanks Jules

Kind regards Julie