Smart convertible, folding roof does not close

Help, who has a tip for me. My convertible deck (Smart 05/05) doesn’t snap in the back left (back hook). Although the cover is pulled forward, it no longer closes completely. In the Berlin Smartwerkstatt you have now hourly new horror reports for me. First allegedly the rear hook was broken, now the complete cassette has to be renewed??. A glider is (probably broken because of crooked drawing). The costs should now move already at approx. 1.000 EUR. What can it be that the right hook closes and the left one doesn’t. Is this just due to the adjustment or is there really a more greeting part to break. I have no confidence to the workshop. I assume that the installer has never taken such a cover apart – and I can now pay for his teaching lessons.