Why my iPhone is just vibrating on calls? And no other response?

This is the order of operations in diagnosing the reason for your device's failure.

remember to remove a battery before any repair.

remember to do A HARD RESET after every replacement. (Home button, and power button for 20 seconds, or until you see the apple logo.)

1) The Connections to the screen are loose: A good technician will remove the screen before replacing the battery, as to avoid stressing out the flex ribbon during the repair. Unfortunately, this may cause the connections to not be reassembled properly. open up the device, re-remove the screen, and attach it again. make sure you hear a click with each connector you apply. Should you have access to it, i would also suggest cleaning the connections with 99% isopropyl for a longer lasting device.

2) The Flex Ribbon has been damaged: Should a technician not remove the screen from the board before the replacement of parts, the stress put onto the flex ribbons can not only have the chance to tear the ribbon, but more commonly, partially sever the circuit attached to the LCD/Digi itself. Many will argue that "A good technician is skilled enough to not have to do this," but this usually just means they want to rush the repair. anyone worth their salts will remove the possible factor of damaging the phone, no matter how small the chance may be. accidents can still happen. In this case, replacing the screen should fix the issue.

3) Image Processing IC: Low quality screens, lack of Antistatic protection, and use of metal tools can cause static discharge which damage the GPU. A much more advanced repair, replacing this IC should fix the issue.

4) Missing/damaged components in the related circuit: There are hundreds of components on a board. using the wrong tool in the wrong spot, slipping with the drivers or even a drop, can cause failures on the Screen. Manually scan the board for damaged or missing components in the areas you have worked, and replace as necessary. (A microscope is very helpful attempting this)

4) Motherboard damage: If ALL else fail, you have a perminant failure in the PLB, and need to replace it.