Start Stop does not work

Hello, my T Cross 1.0 116 hp with DSG has had the problem that the start stop no longer works for about 6 months. Furthermore, I have a much higher fuel consumption than before. 6 weeks ago I was in a VW workshop for inspection. They said the speed of the training course was too high, they set it. Furthermore, the particle filter had to be burned free. The battery meter also indicated that it should be charged. This was also done. After that it had 5 days wall-mounted The daily driving distance is at least 30 km, we refuel Super E5. Even with a 300 km drive over motorways the start stop did not work. The consumption is constantly at least 7.5 liters, sometimes higher. At the beginning the car was satisfied with 6.5 liters at most. Today I was therefore again in the AH. One said I should change the winter tires, that drives the consumption up. There was never an error message either. Also a marten bite is not visible. I should continue driving and watch how it is with summer tires. I feel fooled by the AH and not taken seriously. Does someone have similar experiences and can someone say what this can be all about?