I am not familiar with this model but have had a look at the manual online.
Firstly I am assuming that the red charging light is not flashing, and are you saying that by jiggling the cable that you sometimes get a response?
There are a number of possibilities for a lack of charge:
the mains adapter is faulty - needs to be checked with a multimeter.
the lead is faulty - try another lead.
the charging circuit is faulty - needs to be checked by a Panasonic dealer.
the battery is faulty - try another battery. Although you say that the battery is ok as it comes up with "low battery" when switched on its possible that the battery is life expired or faulty and is no longer capable of taking a charge. rechargeable batteries have a charge/recharge life of around 300 cycles.
Beyond this unfortunately I cant offer anymore help.
Hope you get it sorted.