Free advice, man: Don't admit to doctoring the audio when you're trying to defend yourself. There's some wacky logic behind "I didn't do anything with the vocal track, but I worked on the instrumental track..."
Regardless, I could give the left cheek of a rat's ass about your acapella, I think I asked for YOUR verse to the instrumental you posted and issued some sort of sophmoric challenge towards.
Get cocky when you've proven something, son.