Is $15,000 to install box gutters a fair price?

I am a first-time homebuyer and paid $15,000 for box gutters. I am not pleased with them, as it's been 3 months post-install and I have concerns. When it rains, the porch area slopes and water flows over the side very badly. Also, water appears to be sitting on the rubber instead of draining. There are numerous holes in the seams of the rubber, which I believe could cause severe damage over time. I am wondering if these are valid causes for concern and if the company needs to come back to use seam tape. I am looking for advice on what to tell them to fix. Unfortunately, the company is ghosting me, and I feel my options are narrowing. This company is reputable and one of the few that do box gutters in my area, so I thought they would be the best for the job.