Too busy, sounds like multiple versions of the original song with a voiceover, and the multiple versions you have (the original and Timbaland remix, which I raise my eyebrows at as you're sampling a remix... in a remix) aren't even meshed together well with eachother.
You (?) are singing at a volume significantly under that of the original track, and throughout the song, even before the desync which I will assume is a technical problem, you're kind of off sync throughout. I also question the use of even bothering to post given that you fully admit that it's fked in the middle.
Soz.