Been there, done that, twice.
When I got my new Freesat box it only had an HDMI socket so I got an adaptor (digital to analogue) and it did not work, it only produced vertical coloured lines. Took it to a TV shop and it did the same. So I got another. This produced a B&W pic and no sound.
At that point (after the expletives had subsided) I went back to my old Freesat box with a SCART and I am still on that today. It is just that I cannot get all the channels since they changed things.
If anyone out there in Forumland knows a D to A converter that actually works please let us know.