Sewer Line has "Level" Spot (no pitch)

I recently had my sewer line cammed due to backflowing of sewage into my basement shower. The sewer line was recently rootered and the backflow continued. The camera showed a spot in the piping about four feet outside the house wall and nine feet below the ground. This level area is only a few feet long, but apparently enough to cause these backups.

The location of the dead spot is right near a large tree and the A/C unit, digging would be complicated and would probably kill the tree.

Is there any easier way? Like a pump or check valve system? Or am I doomed to drop $10,000 getting this fixed?

Thanks

pipe

A four foot level spot in the pipe is not the cause of your problem, unless it is a dropped section holding water, rather than a level spot.