For many latops the USB sockets (and many other ports) are hard wired onto the motherboard. This is certainly the case for my Dell and may the case for your laptop too.
If it is the case then when you had a new motherboard installed you had new USB sockets installed since they're part of the unit.
So it's probably not that they broke your existing socket - it's that they fitted motherboard with a faulty USB socket when servicing your laptop. The fact that you didn't notice this for a few weeks should be irrelevant.
Would need to check a service manual to determine whether the socket is part of the motherboard unit - what's the laptop model number?