I do not have advice for you. It sounds more like a question for an attorney or a consumer advocate like Clark Howard or the local news station, etc. Just voicing my opinion that such tactics seem to be increasingly common in modern times. This is such a frequent occurrence in the medical community that Consumer Reports had an article about it some time back. You go to the doctor, pay your bill and leave .... then several months or a year later, they hit you with a claim for some incomprehensible, latin named service that you wouldn't know if you received or not. The upshot of the CR article was that it was coding nonsense that needed to be straightened out. It's very difficult or impossible for the average person to protect themselves from this nonsense. Here, an attorney or C advocate may be able to advise if there's an "out" or what you're within rights to demand from the biller. Good luck.

I can not imagine doing business and not billing your customers. Not sure how he stays in business.

Let me ask - trying to keep it simple - Did he do the work to your satisfaction? Most important - Did you have a contract for what was to be completed and how much it would cost? When you did not receive a bill, question him ( not your responsibility just asking). just thinking that if you had $$ set aside, I would want to pay before I spent it!

If he completed the work, then you owe him the money, if you did not have a contract then I am not sure if can argue the $$ billed about ( like that he charge you too much) I am not a lawyers and this is just my opinion. I would remind him that he was negligent in sending you the invoice and that this is the 1st notice. ( for the record), Suggest if you can pay in installments - I think Yardvaark has good advise to contact someone that has knowledge on hiring contractors and your rights. IMHO you owe him the money if the job was completed to you satisfaction.

you need to start by pulling up your signed contract, any change orders, and compare those with what he's invoicing for.