I live in a tenement with 15 flats. Originally, there were 16, but at some point, two flats were combined into one, reducing the total to 15. We're facing some expensive repair work in the stairwell, and I'm unsure whether I should be paying 1/16th or 1/15th of the bill. I believe I need to check my neighbors' deeds to be certain, but I've had difficulty accessing them. Does anyone have advice on how I should proceed?