Went to buy camping supplies and was going over the selling and buying inventory and cleared it to restart and everything disapeared from olegs inventory. Now nothing shows if i go to buy or sell and cant complete transactions.

Are you sure it hasn't just scrolled down? The inventory in this game has a habit of autonomously scrolling so you can't see anything. It's annoying as hell.

Also, sometimes you'll add an item from the vendor screen and it won't show in the transfer slots, but the price will change to tell you that you're buying the "invisible" item. Clicking to buy it puts it in your inventory though.