美国采购需求：三头肌绳、阻力带手柄、人体工学哑铃、地雷架、附件配件、杠铃地雷球

I recently received the trampoline I ordered, but unfortunately, it's missing a crucial part—the knob needed to tighten the handle. I've checked the packaging thoroughly, and there's no sign of it being hidden or taped somewhere. Without this piece, I'm unable to properly adjust the handle, which is essential for safe usage. Could you please assist me in resolving this issue? It would be great if you could send the missing part or suggest a solution. Thanks!