using frames like that one is everything SINGLE TIME you try go to vender it will run, which can cause problems. use this instead, use overridepulse to go buy stuff from venders.
if(wManager.Wow.Bot.Tasks.GoToTask.ToPositionAndIntecractWithNpc(new Vector3(1,1,1), 55 , 1)) // vectors of the npc, npc ID, Gossip
{
Tool.BuyItem("itemName", Amount);
}
return true;