VacuFlush problems

Hi everybody - I'm having NO luck on this trip. Last trip I had problems with my Vacu Flush toilet. Didn't build up enough suction for a "green light". I waited 3 months for my repair shop to take me in, and after stressing how important this issue was ( my wife and 2 girls found this unbearable ) they found no issue. After another conversation to please check it again as I found small leakage in the compartment, they said all seemed fine. I picked up my rig and of course, same issue as before. Now it's leaking in my compartment as well. I've seen videos on replacing the toilet seal and duckbills. Does anybody know what may be the issue with sewage leaking in the vacu flush compartment but also not building up enough suction for a "green light'?

BTW - I'm done with my service center after this. Problem is - hard to find a replacement in my area ! I need to be my own service technician I guess.