Bosch Washing Machine Performs Poorly and Does Not Remove Stains

I purchased all of my household appliances from Bosch. Because I was working, I didn't have much time to file a complaint at first. When I told technical support that the washing machine wasn't cleaning properly, they suggested that I use stain removers. I'd already used them, but the stains were still there. They then recommended that I use the pre-wash program and the cotton mode. I took their advice, but the money I spent on electricity, water, and stain removers had no effect and only increased my bills. I called the service again, and the technician who arrived was completely unaware of the granulated detergent I use for my child. He claimed that using a detergent that is not in the box but is in a sealed package with no access to air would aid in stain removal. I agreed and added another detergent not on the Bosch list. The technician came, took photos, and the stains on the clothes he washed in the machine did not disappear. They called me yesterday and asked me to run the machine again with a stain remover. I told them face to face and over the phone that even after using a stain remover, the stains did not disappear. Now my question is, why does Bosch, despite being a global brand and selling expensive products, continue to sell its products if they require stain removers for use? I have a child, and I am constantly washing clothes. Should I use dangerous substances? Please take all necessary steps to ensure that each service call not only provides different perspectives, but also offers a solution and supports your product.