My avatar keeps disappearing

I’m still having problems with my avatar not staying with what I’ve chosen. Sometimes when I return to the forum I’m a black silhouette again, and sometimes I’m some random character. I chose the avatar I currently have out of the extremely limited options available (I don’t even know what characters these are) as I have only four or five rows of options to choose from. As a Sims player, I want Sims options, but no Sims avatar options appear for me at all.

I had a similar issue a while back and it got fixed, but it didn’t last very long. What is the problem here?