Help! My tileman allowed excessive mortar into the 2 in P-trap in a shower drain. Its in a slab and so far I have gotten rid of it to where the trap turns upward, primarily with muriatic acid and shop vac. A power rooter won't bend enough with a head on it. I'm reduced to jabbing at it with a toilet auger. Any ideas/tools on attacking this problem? Its a new house ready for occupancy so I dread tearing out the shower pan/slab with its associated costs and risks of hitting cables,etc. Thanks for any help.