Dropped calls

switched to xfinty triple play last year.  Previously had ATT voip and internet, and switched for more bandwidth and speed. Numerous issues still unresolved.  Had service techs out, replaced lines, connectors, etc. Phone calls continue to drop regularly. I'll be speaking, and the other person will be unable to hear me, and say "hello" over and over, then hang up. I can hear them, but they cannot hear me.  Internet sometimes goes out every 20 minutes or so.  Very frustrating. The last tech who came out said it's tied to how much traffic is online at any given time, and when usage in the neighborhood peaks, service drops. This sounds bogus to me,.  ATT was slow, but reliable. Calling for help is an exercise in futility, and just makes me want to pull my hair out.  I have run all the troubleshooting stuff online.  I've got xFi 1, Cisco gateway. Appreciate any help.