Hello I am new to this forum and I would like any stories/anecdotes/ideas you may have....about customers paying you for the work you have done

I am preparing a training course for service engineers and assisting them in overcoming problems they encounter with the customer paying for the call out and / or parts supplied etc.

Do you get this? How do you overcome the excuses you get & still get paid? Any funny stories?

Also (I do specalise in this king of work, but havent done anything for engineers before) are things getting harder for people out there? Do you think people are struggling more?
Regards