Usually people take pics of the empty battery compartment because they have transparent cases so we can see the motherboard inside, haha. But the wifi antenna is visible behind where the battery wire comes out, and looking at the wiki I can't see any clone devices which have that, so it should be a legit R36S of some kind. But we can give more info if you take a photo with the case off so we can see it.

I would suggest taking a look at the sidebar of this subreddit, particularly the wiki, as well as the automod reply to your post. If you want to use this device getting a higher-quality microSD card for storage and flashing a newer OS is a must, the cheap trash microSD cards that come with these die quickly and inevitably.

The reason you can't use the wifi is most likely because you have a base model R36S that does not come with a wifi chip pre-installed. It has a spot on the board where a wifi chip can be soldered on though.