Which practice management software do you use for your practice?

I am the founder of startup and we are building practice managment software for small and medium sized accounting firms,

Just wanted to ask a few questions

1.how do you handle if the clients does not pay on time

2.if the client doesn’t give requested documents on time does it lead to working extra hours and burnout during the tax season to complete the backlog ?

3. If you are not using any software eg excel to manage your practice what problems do you encounter on daily basics while managing multiple clients at once’s

Thanks