Alright, first off this is some Britney remix. This is not the original track.
The vocal track has been sped up considerably. I would not be surprised if the drum beat is some stock drum loop available for some program, and 2 people happened to use it.
I don't think either person ripped anything off, considering they're BOTH remixes. And I'm sure this Britney remix isn't exactly topping the charts and bringing in mad cash.