Many years ago we went to a mekubal. He told us some of the mezuzas we had were posul. He was right.
We had just moved and bought new mezuzos by someone we were told was a reputable sofer. The Sofer would not admit to his mistakes until we threatened to take him to Din Torah….
Going to the mekubal was a bit spookie but was also uplifting and the problem we had soon went after we got new mezuzas