Raise there price for next year. That’s what I usually do. You have to get paid for your time and there using your time every time they call you or have to stop and talk to you when your at the job site. Make them pay for that time. If they become too big of a problem then drop them. Not worth the stress. Specially if there not a big money client. If you need the revenue just go find a couple more jobs that equal what your getting from the bad customers than do what I said.