Took the low bid and paid $4,100 for a $2,200 job

The pile behind the garage is the part that would keep me up. If he dumped the rest somewhere it shouldn't have gone, your name is on the property it came out of, and how much exposure that creates depends on your state's illegal dumping statute. Dump tickets aren't paperwork for its own sake, they're your proof of where it went.

Two mechanics in this that are worth separating.

The pricing one: a trash-out bid is a volume estimate and a disposal estimate wearing one number. At roughly $60 to $80 a ton in most metro transfer stations and 250 to 350 pounds per cubic yard for mixed household goods, disposal alone on a full 1,400 square foot house with outbuildings is commonly $400 to $700. A $2,200 bid that covers that plus two people for a day and a half plus trailer costs leaves very little room, and it leaves none at all once you add two more structures. The spread between your bids was doing the work of telling you the scopes differed. Any bid you accept should state cubic yards or truckloads, and it should state what happens when the actual volume exceeds the estimate, because otherwise that conversation happens on site with your demo crew waiting.

The documentation one: disposal receipts tie the material to a permitted facility. Where liability lands when a hired hauler dumps illegally depends on your state's solid waste statute and on the terms of your agreement, so that specific question is one for an attorney in your state. Requiring tickets as a condition of final payment is a contract term you control regardless.

The assumption your whole revised process depends on is that your vendor has capacity to come back and fix a miss without blowing the schedule. Holding 25 percent only has teeth if the vendor wants the next job. If you are hiring the cheapest available crew each time, retainage is a weak lever, and the stronger one is paying a rate that makes you a client somebody wants to keep.

Naive question. Is a text message a contract here? I genuinely don't know where the line is between a text and an agreement.

Reading this as somebody who would absolutely have taken the $2,200 bid. The 6 days of holding cost is the number I would never have thought to count.