Interesting that you said the customer is "reluctant to pay" and not "refusing to pay." I have been in business for 42 years and lost only $2500, most to bankruptcies, where no one gets paid. Do what you say and when it is due, and there is usually not an issue and if there is, you know it is not you. I've had only three small clients that flat out did not pay, and they are all dead. No, I did not kill them. Anyway, your word "reluctant" tells me that they have some reservation or reason to want to withhold payment and you need to resolve that issue politely and professionally in person, not by mail, yet. If they are brought around to being satisfied, most reasonable business owners are like you and will pay, just as they would want to be paid for their work, whatever it is. Do not take the sign down, unless you would rather have the sign than the other half of your money. It is not legal, anyway and will just escalate any issues if the right to do so was not in your contract. Some contracts do have that removal clause in them. If none of that works, there are all sorts of legal options, and a lawyer will usually send a letter for a small fee and give you advice on options, if it is actually worth it to you. I have sent self-made (internet) legal-looking letters of "intent to file lien" along with copies of the court filing papers ready to go and it got a very quick payment in response. Maybe offer a short payment plan? Be professional and careful with your words and follow through on anything that you threaten, if it comes to that.
