Hello Carlos,
The only successful way to deactivate iCloud lock on a device, is to switch out the logic board. I have successfully done this a couple times. However, the price of a logic board might be more than you paid for the phone and this also deactivates the Touch ID. The home button will still work, however, the phone will not be able to program fingerprints to lock and unlock the device.
If you can find a "for parts" or "used" iPhone, same model that you just purchased, that does not have iCloud lock on it on Ebay, this would be the best option for you price wise.
Hope this helps!