We have had our pump replaced 3 times in 2 years and multiple floats replaced that were excessively swollen. We have had the check valve replaced most recently and still it will not cut off. The plumbing company is now insinuating that we are doing this intentionally. It will work for a little while after they leave and then someone takes a shower and it won't cut off. We have not used any chemicals or cleaners in the toilet or shower. Please help.

Open up the pit where the pump is located, snap a (good) photo of it and post it... I would like to see what's wrong... Back to you... Milo