I had a bathroom installed in my basement. It is bubbling and showing signs of a clogged vent. The plumber installed what looks like an indoor, filtered vent. Thre ventilation pipe does not vent out through the roof but goes as high as the basement ceiling and has a black, cap looking contraption with an internal spring. The plumber cemented this thing in so I am not able to run a hose or wire down to clear the blockage. It seems that my only option is to cut the pipe, clear the blockage, then piece back together with a coupler. Your thoughts?