Copper to Fibre - Home Phone Frequently Goes In & Out of Service

17 months ago my condo was "upgraded" from copper to fibre - ever since then the home phone goes in & out of service.  Get a fast busy when dialling out & no one can call in - they get various recordings or dead air.  A factory reset was done on the box, the box was replaced, an "out" & "in" order were done to break all old connections.  Phone worked flawlessly for about 6 weeks after that but then reverted back to intermittent service.  I gave up in frustration and resigned myself to unplugging everything once a week to reset the phone.  Recently I decided to try again for a permanent fix.  A repairman was dispatched 3 days in a row, bringing a 2nd man with him on 3rd day.  They determined it's a back end issue and I believe had a SOA profile created.  Phone worked for about 16 days but has gone out of service 3 times since then.  Repairman promptly responded to my text 1st time, but has not responded since.  I went back thru Repair Service and they are dispatching yet another repairman.  This will be the 7th time someone is coming out.  I seem to be stuck in the Groundhog Day of Repair Service.  Has anyone else had issues like this?  Please, please, please can a manager take charge and oversee this process.  It seems like a lot of time/money is being spent dispatching repairmen and no permanent fix is ever found.