I have an MI mini-dot mount for the Fast-fire II that might have issues.  Hope you can help me here as the company has failed to respond to my questions...

Although there are no obvious signs of wear on this thing,  the dovetail is loosey-goosey.  Not only does the platform slide laterally along the dovetail, but it also moves up and down a few degrees.  

Also,  this thing does not have the hex button-head screws as seen on the below photo.  Instead, it has regular set screws in their place.  What keeps this mount from flopping up and down like a regular iron sight?

Is there a remedy for this situation? Or is it a confirmed POS?

Mine does as well. It's a shitty design and by using steel and aluminum dovetailed together the aluminum wears quickly and that ruins the mount,

That looks like a set screw directly under the rear sight groove.
This probably meens you have to set any rear sight lateral adjustment before mounting the sight.

Mine was junk, I couldn't get it to hold zero anymore than 30-40 rounds. There are just too many pieces to move around and the clamping screws don't hold worth a damn. It's a cool idea in theory, but I wouldn't trust anything like it after my experience.

Mine was returned for refund. That mount has to be readjusted and rezeroed every range trip.

I hear this repeatedly about the MI, it's a terrible design, real POS.

The winner in this category of mount, is the Attero mount, and it is superb. Hate to keep harping on this one piece of kit, but it simply blows away every AK optic mount i've tried. I run them on all my AK's, and shoot better than ever with them. Solid as a rock, their mounting system is FAR superior to that MI crap.

I have one and it is less than desirable :(

My MI mount works good (rmr model). Im using a 7moa dot on a mini draco. Seems to hold zero after 500 rounds. For my needs I like it, only time will tell how it holds up.

500 rounds is nothing. Time will tell that it will fail. In the  mean time just keep an eye out on where the two parts are dovetailed together and watch for signs of loosening.