From what I know, and have found to be the case, there is no way to bypass or hack the iPhone to go beyond the iCloud lock. No service will be able to unlock the device, no matter what they promise, and it's more effective to throw your money away.
There is an exception to this rule that I have seen, and that is if you have the original receipt from Apple with the serial number of the device on it, Apple may be able to unlock it for you. However even that isn't guaranteed.
That's just my observations, and I think because so many of these have been sold on eBay and Craigslist, that people want a chance to redeem the phone so they don't think that they are throwing money away. Then when they do pay these services, they throw more money away and end up tossing the device, or selling it again to some poor schmuck.
The conspiracy theorist in me suggests that the people that put these sites out are the very people selling these devices, to then make money on these sites. Again, that's just the conspiracy theorist in me.
