Einhell Refused to Sell or Support My TE-CD12 Battery After I Tried to Replace It

Hello, I have been using your products for many years and own around 30 products from the Einhell brand. The battery of my Einhell TE-CD12 cannot be repaired, as I was told. When I tried to buy a replacement, I was informed that it was out of stock. I then contacted your German headquarters to purchase the battery, but I received no response. Selling a product and then providing no support or response violates modern business practices and is disrespectful to the customer. Please provide a solution to my problem.