Hi, I hardly ever collect for the reasons you mention, unless someone is getting out of hand, I personally dont mind waiting for my money as if I dont see one customer I see the next who may owe me for two times, and if they can't put a cheque in the post something is wrong afterall, when I take my car to the mechanic, I go back and pay him!
As for your customer, some people can be differcult, but if we did what every individual customer wanted, we would be running around every night, I say sick to your guns on your plans for collecting, afterall you made the decision for good reasons, if you are concerned about loosing her as a customer right now because you are loosing other, wait for a bit then decide what do about her.
scrimit