Surprise charges from a contractor

[Bryce Andersen]

Recently I had a contractor install LVP in a home I'm remodeling. We got an estimate from him for the project for $2,753. nothing was ever signed. The contractor was terrible to work with and hard to get ahold of. we finally got on his schedule and he pushed us back day after day with a new excuse each time. finally, he came and did the project which took much longer than he said it would. after he finished, he sent the bill for $3,874. That's over $1000 from the estimate. He ended up needing to buy more materials because he didn't measure correctly in the beginning. There were also multiple items he had added to the estimate that we never agreed upon or knew about. I don't think it's fair for him to add additional costs without my approval so I told him I would pay for the extra material and his labor but not the additional items he added which I think is completely fair. now he is saying he will send me to collections to collect the full amount am I in the wrong or is it justified? Also is it even worth it to go to collections over an extra $1000?