When you buy a “bonsai” tree it never really looks like it if it ever did. Majority are a bad examples of consumers society “bonsais”. This one though did have to my understanding a fairly nice trunk, some potential.
First I potted it into “my production” ceramic pot (technically, this one succeeded the best out of all 27 I did last winter).

In this photo the to me good part of trunk is hardly visible. Lots of growth everywhere without any sense and direction has to be cut away. I ended up with this:

On the top was an ugly scar of straight horizontal cut which looked very bad. I tried to make it a dead wood feature. It is not yet finished, I noticed it needs more shaping and carving.
Looking on the above left photo the lower right part of the trunk has a bump. It is the remaining of yet another bad cut which I will also shape later to a dead wood. On the right photo above not very visible is a part of slight reverse taper in the lower third of the trunk. That one I will probably carve out and make a hole or something, trying to shape it like it rotted.
Below some more photos of the same tree. The growth is slowly appearing so it did survive severe cutting. Only the very small branch at the top lost its leaves and obviously I will need to cut it out. 

Photos are not very good, somehow the soil looks very dark so I need still to learn how to make the photos better.