[co] Contractor Billed Me $5,900 For An "engineering Report" When I Thought I Was Getting An Estimate

Location: Colorado

A homeless person started a fire that damaged my detached garage. I contracted with an insurance-related contractor to do the emergency board-up as I was out of town and would not be back for over a week. My insurance limit for the detached structure is around $60,000.

Timeline:

• I signed a contract for emergency board-up/repairs.
• The emergency repair work was completed under the signed contract. I signed a document stating that it was satisfactory (I had friends over who sent me pictures and video).
• I asked the contractor to provide an estimate for the full rebuild. I did not sign a contract for this.
• I got the bill for the board up (covering the garage door that was cut away with plywood) at 1,250. (This seemed high, but since it was an emergency timeline I just paid it)
• They originally submitted a cost estimate for $65,000 which when the insurance reviewed they said they would pay $32,000.
• They then updated their cost estimate to $125,000 and said the garage would take a whole rebuild. Additionally, because zoning has changed, the additional construction would lose 4 feet in two directions, effectively meaning that there would not be room for standard cars to fit in the garage. This was considerably over my insurance limit, so they just paid the limit, they did not review and get back with another number (so I don't know if they thought that 100k was reasonable or 75k).
• I ended up doing the repairs and rebuild myself with the help of some friends as well as some contractors for individual pieces for considerably cheaper than the contractor over the course of several months.
• The contractor is now billing me for an engineering report at a cost of $5,900. They are saying that they needed the engineering report to cover the $65,000 to $125,000 change in their estimate.

The contractor knew that I had a budget (they were aware of the 60k limit), and 10% of that cost for the engineering report seems like something I should have been told about at the very least if not sent approval for. I had asked for them to give me an estimate when I signed the satisfaction for the board up, which I thought closed the door on them billing me any more until I chose them for the rebuild. They never sent me this engineering report, even when I told them that their costs were too high and I would need to go another route, I first found out about it when I got the bill.

I wouldn't even be so upset if all of their fees did not seem so high. (I recently did an engineering report for a similar detached garage in Idaho that cost half as much, but I was told in advance. I know different states but still...)

While I'm still trying to negotiate, without having signed anything beside authorizing the initial emergency board up and a subsequent document saying I was satisfied, do I have a leg to stand on when I push back and say that the cost was too high? Am I legally obligated to pay for something I was not told about?