thank you for your suggestion

I'll look into the custom trim. Thank you

Whomever cut the oversized hole so badly needs to pay for a new oven cabinet, or a skin and some fillers to fix it to your satisfaction. That’s pretty badly done.

I thought so too. Waiting to hear from Home Depot to see how they think the situation should be resolved.

"Whomever cut the oversized hole so badly needs to pay for a new oven cabinet..."

No, the cover for the opening is sitting on the black countertop in the second picture. It is shown in place in the first picture.

It looks like the OP bought a countertop microwave oven. He needs an oven for which there is an available trim kit, to build support the oven to the proper height in the opening, and to cut the cover for the trim kit (if necessary).

Thank you all for your suggestion. Home Depot Rep originally thought that the pre cut opening was a mistake. After checking she determined that was the standard cut for Kraftmade. She ordered a new cover without a pre cut opening at no charge. Problem solved