美国采购需求：步枪瞄准镜、双筒望远镜、观靶镜、步枪瞄准镜环、战术支架、清洁刷

I recently purchased a scope that claims to be shockproof, waterproof, and fog proof. However, every time I try to use it, I end up with only one shot before the sighting goes off. It keeps falling out after the second shot, which is really frustrating. I'm looking to return this scope and either get a full refund or exchange it for a more reliable one. I spent around $80 to $88 on it, and I really need a product that holds up during use. Please let me know how to proceed with the return and exchange.