I have never seen PVC connect to the tile system..

I have never seen PVC connect to the tile system. weeping tiles are flexible black hoses, perforate type are usually have white fabric sleeve outside and buried under ground, then they connect to a non perforate line which it brings the water to storm line.

from your picture, I can almost sure them PVC pipe are plumbing for a bathroom.

did your contractors determine where the clog is? under the basement or the tile to outside storm line?