Foxgear Multitune

Have a brace of fine acoustic / electric guitars. Use multiple tunings and was hopeful but, so far, it doesn't seem to work as promised. I can see all the strings but when you tune it doesn't track the changes. I thought it needed a compressor at first to tried that. Didn't help. Wrote Foxgear and no reply yet. It's pretty, though! I gave it two stars for that. While I'd love to sell it, I feel guilty doing that. The guy who sold it to me said it worked.
I see they have a five year warranty. Maybe I'll send it back to them.
It works like a standard tuner - one string at a time. But I already have many of those.