has there been others that had brakes and rotors put on that after driving it 100 miles they get burnt up and they need to charge another 100 dollars to fix it

Check your master cylinder, i think it may be activating too much!

The brake pads went bad. Or rotors. Or both?

Might check your calipers. They might have gone bad and squeezing all the time.

No

Nope. They may have used low low quality parts.

Never seen brakes go bad that fast, even for two feet pedaling drivers

Sounds like shoddy work