Phone "upgrade" failure

We have had reliable phone service from COX for over 30 years.  On December 15, 2017 we "upgraded" our phone.  Shortly after the "upgrade" all our phones, (8)  stopped working.  Fortunately we only use our COX phones as backup in an emergency but after the recent problems I question whether that will be an option anymore.  We scheduled a service call for today, but no one showed.  Wasted 2 hours of my time for nothing.  I had to schedule another service call.  I hope they show.  Been without the backup phone for about 3 months.  I asked if I could go back to the way things were, they said no everyone is getting converted.  I am frustrated.  Between the cable , internet and phone our monthly payments resemble a car payment.  If this is not resolved permanently this week I might have to look at alternative vendors of these services.  Or maybe it's time to "cut the cord" and downsize.  Companies should not roll out products that don't work.