Review on Microshift Advent Medium Cage 9-Speed Rear Derailleur - Black with Clutch by Nathan Akers

I don't usually spend time on reviews except in this case the product isn't working properly and I've spent hours trying to see if I can fix the problem with gear shifting. as I was using an 11-40 9 speed transmission and spent hours researching online as I really wanted to see how the product worked. But that's not the case. . When I sent it back the seller said it had been used and I was only eligible for a partial refund. I was still okay with that and didn't bother until other excuses popped up in messages such as: B. not to be used with the right switch? Maybe it's right? but it looks like another 5 people have the same problem. I'm not a bike mechanic, but I'm very knowledgeable about bikes and how different parts work, and have built several bikes. This is just to clarify that I understand bikes.