I feel your pain Tony, I really do. Yes I have been deceived by customers more times than I can remember.
I am getting older now, and hopefully a little wiser. I used to go out of my way to accommodate new customers, but found that when I needed them to reciprocate, they were not so eager to work with me. If someone new wants my services, I try to fit them in around my existing schedule, but don't reschedule work I already have planned just to please them. As for pricing, don't ever price a job without seeing it first. Again, I have done so in the past, and it is always more favourable to the customer.
As for promises of regular work, people always say what they think you want to hear, and again I've experienced this many, many times, especially here in Ireland. People here mess you about for fun. I would rather people to be honest with me from the start. Once they have lied, any trust you had in them is gone forever.
Don't let any mistakes you make eat you up. Take it on the chin and learn from it so as not to let it happen to you again.
Best wishes,
John.