Email Filter Rules are being removed

I had created filter rules for moving specific senders to one of my folders.  The filters were active for quite some time, but in the past few weeks the filters have been removed.  I created a new filter to process the emails again and it worked for a few days and then the filter was removed again.  I tried one more time to create the filter from the inbox move command and it was working for about a week and then disappeared once more.  I called Xfinity support, but they were of no help at all after about an hour of discussion with them.  So, I am looking for some assistance here as to why my filters are constantly removed.