I'd like a few examples of what you are experiencing as ' cheap, complaining and disrespectful"
Raising their price or pushing them way out on your schedule might work with some people
I'm a pretty straight forward person, so if anyone is disrespectful to me I would immediately call them on it to find the underlying issue
If the complaints involve frequent reservices for cleaning then I would spell out why my price is so high, that I including the cost for the return visit that I am inevitably going to make
Cheap is the easy one, I have competitor coupons in my truck, just hand them one and explain how it works regarding up sells and restrictions.
The bigger picture is, if their payment clears and you made a reasonable profit then suck it up. Most people are great to work for.
It's not like we work 10 hour days in an office for some douche that takes credit for our hard work and shits on us on a daily basis