Bosch bad design refused repair or replacement under warranty

Bought a Bosch dishwasher at Makro in February and found a design flaw that makes the dishwasher not dissolve the detergent tablet and therefore fails to was the dishes clean. I brought this under Bosch attention and they log a repair. The technician called me and said that it is the tablets that is faulty and not their machines without coming out and look at the issue. The more I tell him that this issue never happened on my Defy the more he said it is bad quality on the tablets and not the machine. I need a letter from Bosch so I can return the machine for a full money back warranty so I can purchase a defy again. Very bad service and bad machines from Bosch.