Please provide a picture of it (so I'll have a better understanding of how it looks like, which would would help me locate a replacement for it)
But set replacement aside, I think you might be jumping to conclusions. It's possible that the connector itself is fine (maybe you just need to resolder it so it'd make better contact!) or it could also be a problem with the USB cable they use (or an issue with their USB port/computer)
Replacing the connector may not necessarily fix the problem. You could do a simple checkup to determine if there's something wrong with it though!
Take a micro-usb cable, cut it a bit after the connector (as in, a bit after it connects to the tablet), strip the insulation off it (and insulation of the individual wires too) and then measure the resistance from end to end (wire>point on the USB connector), if everything reaches from end to end (and nothing is shorted) then the problem is not the USB connector (but regardless, resoldering it might be a good idea just to be on the safe side)