I recently moved into an old house(1952) in north Texas. The house had foundation repairs in 2/2011. I started to notice stress cracks and called the foundation company that had a lifetime transferable warranty. They suggested that the piers were working just fine and that I might have a slab leak because the home seemed to sag towards the middle. I had a leak test performed and learned that I had 8 sewer leaks. They busted three holes in my house and everytime the dirt was dry around the leaky pipes. Since then, I have also heard that a sewer leak can not cause foundation issues. After $11k in sewer leak repair, I'm wondering if there was any need to actually have the sewer leaks repaired. Was the foundation company just trying to get out of adjusting their piers? Maybe their perimeter piers had actually lifted up and caused the appearance of the middle of the house sagging? Any advice?

Thank you!