(Sorry to those who pmed me today as you can see I can't receive any pm )
Somehow restarting the client works but I'm afraid this bug will happen again
You can buy shop items anywhere where guards are.
You can do this by trading the npc that has the shop and teleport away before the interface open(trade from a distance). Then you can just find a guard and pickpocket it. The interface will show up.
Also there is a minor bug with teleporting, when click on a teleport such as Grand Exchange, Falador, Alkharid, and Barbarian, before other players or npc attack you (or click on those teleport before you attack them). You can click yes while in combact and it will teleport you to GE or wherever want clicked on it, it will ignore the 10 seconds out of being in combact to teleport and teleport you instantly like spell teleports or teleport tabs