Should we bother disputing these overages on a new hone

My husband and I signed a contract with a builder at the end of December 2021. That contract clearly states in more than one section that if there are overages, both parties must agree on the cost and if something is going to be more expensive than expected the buyer will be notified. We are nearly done with the build and are about to close. When just this past Friday, we were informed that we owe an additional $17,000 of which we approved 3,782 previously. These charges are all infrastructure and survey costs. I believe the earliest of which the invoice was from May 2022. We were never informed and nearly all of these things. Are double what we were estimated on the original contract. Yet another issue is the land clearing is above market value and driveway stabilizer that we signed off on for $3000 was only $2700 according to the invoice that the builder received. I do not know if we have any case here but I feel like this is at least a breach of contract-please advise