I got rid of all teeth on every charger and usb lead and mine has still broke, it hasn't broke off or even become loose but my phone will not charge or accept that it is connected by any lead,
Apart from when it is switched off and i insert a lead the dim nokia logo appears and a usb symbol shows top right for 3 secs and and then shows the booting dots then switches off and then loops over and over again doing the same thing.

I believe these are classic broken microusb socket symptoms but i haven't had it confirmed yet.