Charging problems (similar to bad contact)

Hello,

i don't know what to do.

My iphone won't charge anymore (well, it does partially):

1)my iphone is not "seen" by any pc (i plug it in but nothing happen and there is no charging at all)

2)when i plug it to my charger (original one) sometimes it charges, sometimes it says "charging not supported" with this symbol http://goo.gl/FZXqXK).

3) whet it charges, sometimes it charges for some minutes and than goes in "chaging not supported", and if it charges, i see (in the battery icon) the icon that keeps switching between the first to the second type of battery (look here http://goo.gl/E3wqqh)

I alredy changed the battery (it doesnt gave me any life signs, i think due to problem nr. 3) and the dock connector, but the problem is still here.

What should i do? (no warranty anymore).

The iphone is jb, could it be a software problem?

thank you very much and sorry for my english, i'm italian.