Before spending money you could try this:
A common problem with micro USB is the build up of dust in the socket. Every time you insert the plug, dust coming from your pocket is pushed in, which gradually fills the socket. The result is loss of connectivity.
The good news is that it is very easy to clean the socket. First remove the battery in order to avoid any short circuiting during the procedure. Then take a needle and pick out all dust and dirt from the USB socket. You'll be amazed how much will come out. A magnifying glass may be helpful. Once the socket is clean, reinstall the battery and cover.