Yeah but if you are doing shit with no permits and no contracts then you gotta play it cool or else they don't pay you at all. You attract more flys with honey than vinegar I believe is the saying.. if she wanted you to finish one more job before paying you I'd finish that then put her on on the black list. Like you said you've never had a problem with her so cut her some slack and get your paper. If she don't pay, pinky don't answer. Also no matter how good a client is, if you are doing work that's in the 1000's of dollars, maybe figure out a better way of securing payments before work is complete or at least on a daily basis or else you arent showing up the next day... People love to take advantage of nice helpful people and I don't wanna tell you what to do but that's what i would do..