Is the non-working micro USB port located on the docking module (lower part), or is it the one on the upper part - the “tablet”?
As said above, it will be hard for most DIYer to replace the micro USB port on the “tablet”, but it’s quite easy to replace it on the docking module. To gain access to the charging dock board do this:
# Remove 4 rubbers on the bottom case
# Remove 10 screws on the bottom case
Here is the original part number for the logic board (motherboard) of the docking module: 90NX00B0-R10030
One of these (used) is currently available on eBay: https://www.ebay.co.uk/itm/302658111849