Try running your "business" like other businesses run.

Does you bank call you, call you, and plead for you to make your car loan payment? NO

Does your power company call you,  call you, and plead for you to pay your power bill? NO

They are businesses and have rules for payment you must follow, or they come and get your

car, or cut off your power.   Why not operate your business like a business?  Quit begging the

slow payers, and drop them.   Less tension, maybe find a better client, and enjoy life.