There's customers out there that want a cheap, half-a-job-bob standard of work, there's customers out there that want something approaching reasonable and acceptable and there's customers out there that want quality, professionalism, polite manners, and a give and take working relationship.
Some you'll find on FB, some you'll find from your website and some will arrive because they've heard about you through the grapevine and like what they hear.
You cant please them all and you won't secure them all. Some are meant to be and some ain't.
Stop fretting over lost ones, they obviously don't fit your customer profile. And if those lost ones are quality customers you possibly need to look at your working practises.