Is $1,900 to re-pitch and re-line a Yankee gutter on the lower roof a fair price?

In May 2024, I paid a local roofing company to replace the roof on my two-story home, which included re-lining and tarring the built-in Yankee gutter on the lower roof, and replacing shingles on my detached garage. Recently, I've noticed water pooling and not draining into the lower roof's Yankee gutter during rainstorms, causing water to pour over the side and wash away landscape mulch. A service guy from the company confirmed the gutter isn't pitched correctly, with the drain being the highest point. I've lived in this house for 10 years, and drainage was never an issue before this roof replacement. I believe this is a workmanship and warranty issue on their part, especially since I paid $11,500 in full for the original job. I am disputing their $1,900 quote to fix what I see as their mistake.