What he is doing is completely out of order and definitely unacceptable. This is not the way a legitimate business should carry on their affairs at all. There are proper channels to go down to get back money owed by a business. This man's way is entirely wrong, and I suspect he knows this anyway. They sound like the type of business that should be named and shamed, as they do not sound like they are behaving ina ligit and legal way regards running their business.
However, I do think that you yourself have gone about this in the wrong way too and are not blameless here. You owe the firm money and have left it for 2 months. Now I know if you are having financial diffculties these things can get on top of you and pushing them to one side and ignoring them can happen. But the firm rightly want their money and you really do need to pay them for services done.
The damages you mention should have been brought up immediately, not a few weeks later. Two months on I think these are probably now irrelevant. Besides they should be insured, either through the business or your own insurance.
You need to pay this firm and fast. You say you don't have the money? Can you get an advance from work? Can you get a loan of some form in a legitimate way from a bank, etc? Is this the only debt?
Have you contacted the business direct (not though this man) and asked to make a payment plan where you can send money direct to them, over a few weeks? (Do not agree to them coming to your house about this)
Do NOT meet this man at all. Contact the police and make sure they are aware. Make sure you tell them they know where you live, have been to the house and have threatened you, and that you feel that you and your daughter are at risk.
Keep a record of all contact you have with this business from now on.
You have not paid them. They should have their money. Now you need to sort out a way of ensurring they get that momney, but in a way that you actually can and without this nasty person threatening you and your daughter.