How to talk about discontinuing giving offline piano lessons to a student who doesn't have the resolve to follow through with it?

I (26M) provide online and offline piano lessons. I started teaching a student (27M) about 3 months back. They are very complacent regarding the lessons and I don't feel the seriousness/dedication from them and at the same time I don't get paid properly. I am in a bind since this student got to me through someone I know and hence, I'm unaware of how to deal with the situation.

How do I deal with a student when they:

1.⁠ ⁠Don’t pay me until end of the month. (I request them to do the transfer on the first of each month)

2.⁠ ⁠Cancel/Ask to reschedule each lesson each week at the last possible minute.

3.⁠ ⁠If there’s any lesson which did not take place, even if it didn’t take place due to their last minute notice, they don’t pay for that lesson.

4.⁠ ⁠They don’t communicate, let’s say I messaged/called them today, they wont respond until a week or more.

  1. Often take calls/check messages during the lesson which sometimes go on for over 10-20 minutes.