My guess is the microwave is trashed. Maybe not much actually wrong, but 1. finding it, and 2. correcting it, are probably prohibitive.
This Amazon search "0.9 cu ft microwave" netted a number of models around $100. Take a walk around Walmart's appliances, some are much less.
If yours is mounted like ours, the mounting brackets can be transferred to another microwave. Just find one with the same dimensions or close to the High Pointe and trim or add molding to adjust the difference.
It should be safe to drill holes for the brackets into the new microwave. Still, make a drill stop so it goes just through the surface and can't poke down farther.