Exchangers may be disabled from the monitor for various reasons, including technical ones. Unfortunately, it is not possible to indicate specific points.
Is it some kind of automated method, when you can't exactly determine the reason? Don't you have some record of your relations with each exchanger?
For example, how do you manage the case if they request a re-listing with the justification that they have corrected the deficiencies?
Finally, it would be useful if you could provide more information about Imexchanger, just because of brett6934's case. More transparency always helps to strengthen trust.