Tchibo Product is Dysfunctional and of Poor Quality

My product is not working well enough. So I wrote to complain about this and add the video. Several days later customer service called me. She said, "We saw your video so if there is a problem with your product, deliver it to the store".I said to her I haven't got enough time and I m sure the store will not accept this. Because it is working but not as promised. The problem is that the product is dysfunctional. But she insisted I deliver it to the store. Then two days later Tchibo texted me you can get it.I thought it must be a joke. Because the technical unit had said the product is working.I didn't say this is not working it is true the product is working but it is not working in line with what was promised so what I was expecting.