I have observed two things -
1) Yes, it does not charge in some cases. I have a power bank cable, with this cable it charges for some time but then it just stops charging without any reason. If you reinsert the plug, it starts charging again.
Other times, it does not charge with USB ports, for example my car music player's USB port. But what I have noticed is, if USB connectivity mode is changed from MTP to MSC or vice-versa it works.
Also some cables do not have two spring notches, and fit quite loose. In such cases pushing cable vertically up or down gets it charging again. But this is very very rare case.
2) I was not able to charge it from front USB port of my PC, but when connected to back USB port, it was charging fine.
My conclusion is, it does not charge if charging rate is too low or mode is incorrect.
I would suggest, try with original Sony USB cable in your office and check if it works. If still it does not, change connectivity mode. Else its a cable issue(not exactly, but phone and cable have some mismatch).
PS - I had similar problem with my chinese tablet. Out of more than 5 cables, It charges with only one cable from Nokia(it does not even charge with original tab USB cable
). I think there are separate data pins and power pins. But data pins can double as power pins. I think there was some damage to the tab USB pins, because of which data pin no more works as power pin and hence it does not charge and requires cable having power pins. Can somebody throw more light on this?